⚔Learn Katana Martial Arts from Anywhere Worldwide with Let’s ask Shogo⚔ Sign up here: www.patreon.com/lets_ask_sekisensei I provide the perfect online lessons for anyone worldwide who wishes to dive into the world of katana martial arts through my style, Kobudo Asayama Ichiden Ryu. I, Shogo, a student myself, will also participate in every lesson and interpret everything in English. 1. No previous martial arts experience is required; you can catch up anytime 2. Every lesson will be recorded and will be available to rewatch anytime 3. You can join even if you belong to another Ryuha style 4. You can receive official Dan ranks by taking exams online 👺Learn More About Noh Theatre from an Active Professional👺 We operate the best online community for a deeper understanding of the mysterious and enigmatic world of Noh theatre. You can learn about Japanese history and religion while regularly watching Isumi Sensei’s performances with my, Shogo's English interpretation. Sign up here: (Coming Soon) 🗡Where you can meet me in Kyoto, Japan | Yushinkan Samurai Training with Modern-day Musashi🗡 A 120-minute experience in Japan where beginners can learn how to wield, draw, sheath, and swing the katana from the modern-day Musashi! I, Shogo, will be your interpreter to lead you into the wonderful world of samurai martial arts! Make your reservation here: www.airbnb.com/experiences/4577764?locale=en A video of me visiting this experience: th-cam.com/video/MqBCAC42zAM/w-d-xo.html 💰Please support me through Ko-fi💰 ko-fi.com/letsaskshogo 🗡The BEST online katana shop for martial arts (Iaido, Kendo, etc.): Tozando🗡 tozandoshop.com/letsaskshogo Everything I use for my katana training is bought at this shop! I still use the first training katana I bought in 2016, and it is still in good shape! 🥷The recommended online katana shop for decorations and cosplay: Mini Katana🥷 minikatana.com/SHOGO *Get 15% OFF all their products by purchasing through my affiliate link ⭐Who is Shogo? What is this channel about?⭐ th-cam.com/users/shortskZbyd0OfdC4 ⭐MY DREAM⭐ “To make every Japan lovers’ dream come true, by making Japan a more secure, comfortable, and safer place for everyone to visit, study, and live in.” th-cam.com/users/shortsWFF3AhN0LXE ⭐Instagram⭐ instagram.com/lets_ask_shogo/ *Please ask me questions through the DM here!（⚠I do not use e-mail）
One of the fun things about the curved katana is that the curve isn't forged in with the hammer, but created during the quench, through the careful use of the clay through differential hardening. You can find footage online of bladesmiths quenching such a blade in a clear tank and see the curve developing. It's eerie and fascinating.
It's both the result of the forging process and the selective quenching actually. The blade's curvature is also refined afterwards, using a hot block of copper for example. There are many more variables that influences the blade's curvature. Interestingly during the quenching process the blade curves frontside before going back and settling to the intended shape. You can see this in the fishtank quenching videos you mentionned.
@@UryendelNo , the clay let the blade cool down slower were the clay is thicker . It colls down slower at the back and faster at the edge and this creates the curve .
@@5co756 if that was the case you wouldn't be able to make a straight blade. And the clay doesn't prevent cooling, it prevent heating Katana blade are drop t in a bassin parallel to the ground with a movement that create the curve. Now if you want a straight, you drop the blade at once in a tube perpendicular to the ground
@@vids595 ninja were not really assassins in history they were more intelligence gatherers and a lot of them were actually samurai. Literal undercover officers of the state.
I've been playing Like a Dragon: Isshin! lately and have been learning all about the Shinsengumi and the Meiji period. Thank you for providing more information about this very tumultuous and interesting point in Japan's history. And welcome back Shogo!
Just a small nit-pick about the purpose of the curve. Although said curve DOES make for a better cutting/slashing implement vs a straight blade, it is NOT actually any sharper (assuming equal craftsmanship). The improved cutting dynamic has to do with the relationship between the blade shape and the natural arc that a human body will produce when swinging it. Think leverage, surface area, and ergonomics rather than inherent mechanical sharpness. Great video! Super interesting!
This is actually not true. a light curve does not impact cutting capacity of a sword directly in most cases, the only impact is in the fact that it makes it easier to feel the edge alignment. Curves do (stronger curves more) increase the ability to draw cut, but draw cuts are very uncommon in Kenjitsu or Iaido and are only common (as far as I know) in fighting styles with very curved sabres.
@@deltrex on top of this, a curved blade also increases the pressure at the edge, the smaller the contact area, the better the cut, it's why scissors have their distinctive shape, rather than just clamping 2 parallel blades together, and why axes usually have curved edges.
As an overseas kendoka I was super surpried to learn so much about it in a non kendo video. It also funny that kendo was used both by the Shogunate in the form of the Shinsengumi and by the Government with the Battoutai. "We may have our differences but we agree on one thing. Kendo wins wars"
I cannot agree. Shinsegumi used classic gekiken (free sparring), look at Tenen rishin ryu. Yes, they used similar gear, it is ancestor of kendo, but whole gekiken is ancestor of kendo, which is sport with rules, and gekiken is training method. Yes, i see videos with "old school kendo", but thats practicaly gekiken before rules was setted.
@@23Disciple Gekiken was a gamification of the uchikomi keiko of the jikishinkage ryu, which was first made into a sport within the Nakanishi-ha itto ryu and popularised by the 14th headmaster of jikishinkage ryu Sakakibara Kinkichi, who founded the Gekken Kogyo. Uchikomi keiko was a corrective measure for "dead" kata, gekiken since renamed to kendo was always an extracurricular sport. Free sparring is a very modern concept, the people of that time would have had duels, the purpose of which was to prove their system and skill. The word for a duel between students of different schools is taryu jiai not gekiken.
I have always been fascinated by Japan it's people it's culture it's history I've got a lot of books on the subject Your channel has greatly expanded my knowledge thank you
This was indispensably informative, Shogo-san! This clears up a lot of my own confusion and misconceptions about the change in blade styles during the Meiji Restoration Period.
The curve also increases the length of the cutting edge without increasing the overall length of the sword, making it slightly more convenient for carrying and close fighting.
None of those things make sense. What's the advantage in having more cutting edge without more reach? The metal definitely doesn't become stronger because it's curved. There's absolutely no principle that would make that happen, unless the sword was extremely curved, like an arch supporting the weight of the wall above it. The curve in a katana is way too slight to have that effect. And what does it have to do with a bow? A bow bends to store energy, which is then released into an arrow, which has a point. That's the only sense the bow uses curvature to project energy at a point, but none of those mechanics are in common with the katana. The only advantage to the curve is that when you swing a sword, you move it in an arc, and a curved blade more readily follows the arc as you draw it across the thing you're cutting, therefore making the cut easier. Also if you're hitting a flat surface, less of the blade comes in contact at a time, so it exerts higher pressure. But you never hit a flat surface with a sword, so that doesn't really matter. It matters when cutting veggies on a flat cutting board.
@@ericthompson3982 you don't increase *effective* cutting length - cutting length that you can use. Why? Because the curve retreats towards you! This reduces the extra reach you're technically given. You're absolutely right about geometry, but you can't suddenly "straighten the sword" during a fight to make effective use of that extra cutting length. A straight-blade with a couple inches LESS BLADE would have the same *effective* cutting length as a curved sword with a couple inches more blade, if you follow what I'm saying
I still remember Sakamoto Ryoma had a straight sword called Mutsunokami Yoshiyuki. I hope I'm right because I've been playing Touken Ranbu for a long time.
A very informative video. Love hearing about Japanese history (along with history of weapons in general) and hope to some day visit. You've just gotten another subscriber from me!
I think you are right about the 'ninja sword' not to mention the whole ninja panoply. Movies aside, a spy/scout and a commando are very different things. If a spy does his job right, no violence ever happens; he or she blends in, does nothing suspicious and sticks to his story. Much safer if he isn't armed at all. Most special 'gadgets' if any are reserved for the most dangerous parts, which would rarely include assassination (e.g., Operation Valkyrie) but more commonly communication with his handlers. Ninja commandos if they existed, no doubt trained for night raids and wore camouflage, but their weapons and gear was likely not otherwise different.
I love the presentation style of this channel and Seki Sensei’s. Showing me a table of contents seems like it would steal the video’s thunder, but in reality, it usually piques my interest, while setting an expectation of what’s to come. It’s remarkably relaxing.
*sigh* No. The curve came about because smiths in the 8th century started making blades with a low Carbon steel core so that there would be fewer broken Chokuto in battle... and they discovered that that new composition caused the blade to curve in the quench, creating the Tachi. Straight Chokuto and curved Tachi of that period were identical in every way except for the composition that caused the curve. The curve wasn't the goal in the beginning: it was a happy accident that they found had advantages for horseback and draw, so it replaced the Chokuto, but the reason for the change in composition was to have blades whose spine would bend without breaking, NOT to have a curved blade. And the later era policemen's blades were straight because they were made fast and cheap with one grade of steel instead of two or more, so the differential hardening from the clay would still give a hamon but the blade would not curve in the quench, because the core steel wasn't a different Carbon content than the edge steel.
Awesome video as always Shogo. Shogo I always look forward to watching your videos on all kinds of topics about Japanese 🇯🇵 culture keep up the great work.
As always, really interesting. One thing though. The katana or the odachi were curved not just to be safely drawn on horseback, as you say, but to deliver deeper cuts while moving. One of the reasons why the monouchi was the sharpest part of the blade, for the reach.
no, they were curved so they wouldnt hang up and pull out of the rider's hand when slashing at a gallop, curved makes blade slide across target rather than bury or grab
All I want is for you to continue creating these videos and including as much information as you possibly can! It is always exciting to learn something new, especially from someone knowledgeable about the topic. Thank you very much. ☺️
Curves do nothing for balance and certainly don't increase sharpness. 1: Balance is impacted by the profile taper and distal taper of a blade and also by the weight of the handle in relation to the blade, a curve does nothing to make a sword feel lighter, especially a light curve as it is on the Katana. It does however make you feel the edge alignment better. 2: Sharpness is a combination of edge profile (or thinness) and level of polishing. A curve does not make anything sharper.
The curve does mechanically help in cutting. Think of it as a kinetic energy transfer, with a straight edge if you hit something the entire edge makes contact with the object at the same time, imparting its kinetic energy evenly across the object's surface, cutting it in the process but diffusing the energy a cross a larger area. Now consider the curve of the sword. You are still imparting the same kinetic energy as long as the are the same lenght and weight right? Yes but the difference is that the moment the curved sword makes contact only a very small part of the edge makes contact first concentrating the kinetic energy into a verty small point. This increases the cutting power dramatically despite both examples involving the same potential kinetic energy.
@@alexisrivera200xable that would only be true if the object you are cutting is flat and the edge hits it perfetly perpendicular. In reality almost nothing you'd want to cut with a sword is flat and also any area on a Katana that is about the length of a hand (so the size of a target) will seem basically streight because the curve is so small it is almost imperceivable. And most targets are at least a bit soft and elastic taking away even the last bit of theoretical advantage such a slight curve may have.
As a lifelong kendo/iado student, I truly appreciate your reverence for the katana and the various disciplines that have evolved over the passage of years.
Well actually, regardless of the "katana" topic, you are perpetuating a myth of curvature making it sharper. Yes curvature do lower a proportion of the blade contact length which in theory should multiply the force. But It works only with much stronger curves. With something like Shamshir blades. And still the test shows negligible effectiveness compared to straight blades. According to scientific experimental data, curve of the katana blade does literally nothing to make it perform better in term of cutting ability.
It also helps with aligning the blade during a cut, which also perpetuates that myth. It makes it easier for people to use even without as much training with blade alignment.
swords with stronger curvature were a thing, but afaik, not common among the katana you're probably thinking about since those are a result of sword regulation during the 1600s or 1700s?
I've also heard this but one thing a lot of people often miss when talking about it is that fighting techniques make essential to the shape of the Katana. They are easier to draw with the curvature for example. This doesn't make it superior in cutting power or anything and indeed they are harder to handle than a long sword for example.
It's been widely reported and proven that the curvature was as a result of the dissimilar metals used in the production process, for the back and the cutting edge, and how they contracted differently when quenched. The cutting edge was the primary focus, and then the balance between flexibility and rigidity. The easier draw, better cutting, etc, was secondary benefits; and the became the reasons why the production process stayed.
I thought the curve in a katana was due to the iron spine of the blade shrinking more in quenching than the steel core. how then do you prevent this to make a straight blade?
You can just make a counter curve in the blade prior to quenching, instead of starting with it straight. That way, when you quench, the differential shrinkage reverses the counter curve to end up with a straight blade,
A curved blade doesn’t make it “sharper”. Rather, it assists in slashing ability as a separate factor from sharpness. Sharpness is simply the quality of thinness in a blade.
No, that's a misunderstanding; they are forged curved. The quench does briefly cause a reverse curve, but it comes back to the same curvature when the temperature equalizes.
This period would be one where the ancient techniques were coexisting with modern Western metallurgy, so it's possible swords could have been used that were made from cheap imported steel billets rather than tamahagane, which is easier to track and control. IIRC part of the reason for the curve is a hedge against impurities in the blade, you have to slice along the length of the blade rather cut or hack with one point of contact, and this wouldn't be needed in a more uniform, industrial product, so they were free to match the form of the swords used in kendo, though the need to hedge against impurities had long passed by this point in history So, yes, especially as the differential quenching using clay was a specialised technique, the fact that curved katana needed specialised techniques to both make and use and straight ones less so, it was easier to supply a rebellion with straight blades, similar to how large European armies generally used straight blades and curved blades where for specialists or officers. Thinking about it, this might also be why ninjato(if they actually existed and weren't, perhaps, inspired by the Battotai) were straight. A curved katana with a hamon might as well be fingerprinted, so connections could be made to who made it, and then to who might have bought it, whereas a straight blade with a simple handle is essentially anonymous and easier to discard during an escape and replace
It's a fascinating thing to consider as a western fencer and Blacksmith used to wielding mostly straight blade swords. The simplest answer is that they are FAR easier for new troops to learn quickly, as they can focus on the thrust in a fight. While Tachi and Katana are powerful cutting weapons they are VERY difficult to thrust with powerfully. I am NOT saying they can't or that practiced wielders are unable to thrust effectively, just that it's far more difficult for someone used to a straight weapon to do. I have zero kenjutsu training, and only a minimal number of times doing kendo, but I did fence in college and then got into Hema (SCA back then) about 20 years ago. I have cut and handled Katana many times too so I'm only offering an account of the experience of going from an arming sword, jian, and long sword. Nothing I'm saying is to contradict or overrule the information presented here.
My personal experience is that straight and lightly curved sabers thrust about the same, katana are usually pretty lightly curved so I doubt it makes much difference.
@@atom8248 I found it significantly harder to be accurate and to pierce the same target to nearly the same depth (stacked tatami mats or other materials). It might be much easier for anyone who does hema sabre or another sport/MA that uses swords with more arc. I do feel a difference with some Dao that have a straight lower ⅓ to ½ and keep most of the mass centered on the grip. I notice the weight of Katana/tachi that's behind my hands throwing me off, or at least that's the best I can describe it. It's possible I've only handled Katana on the longer more curved side, closer to Tachi than a late Edo period blade would be as well, I've seen a number of blades in museums as well that would tend to be older and original made as Tachi so my impression of them may also be skewed to the ones I used being representative of Katana generally?
I am thankful to have watched this! Your knowledge of history is something I would like to see more of. I will be checking out stuff from time to time. Well done!
The best explanation I've heard for a curved blade, is that when slashing, it concentrates force on a smaller area than a straight blade. Hence, it's better for slashing cuts.
In my view, that is not entirely true. Straight blades can cut just as well in open spaces, and the katana only has a mild curve so it doesn't really contribute to this supposed cutting "power". What is more plausible is when you start looking at actual fencing techniques and systems. In Historical European fencing, straight swords and curved swords utilize different techniques to accentuate their strengths. Broadly speaking, straight bladed swords (longsword, rapier, smallsword, etc) use 'long distance fencing' strategies to take advantage of the sword's tip to hew and thrust. The longer your straight sword, the further distance your strike can hit. Curved bladed swords (sabers, cutlass, etc) use 'short distance fencing' strategies to take advantage of the sword's ability to slash at short distances. That is the real purpose of the curve. Imagine a sword fight happening in an elevator where there isn't a lot of room to fight. A curved sword can slash using lateral movements, whereas a straight sword is more restricted in its movements. Curved swords are more adaptable to close-distance fight situations, such as indoors. Katana is probably curved for this reason. Straight swords have a reach advantage in wider-distance fight situations. That's why it's very hard to fight against a longsword or rapier using a curved sword. It's not impossible to win, but it definitely feels like an uphill battle for the curved sword wielder. I surmise that the Japanese wielders of straight katanas realised this advantage.
@@kissing88 I'm thinking physics. In a slash, the entire straight sword makes contact with the target while only a portion of the curved sword makes contact. Same force over a smaller area for the curved sword means more pressure. I recall the explanation coming from James Williams, the aikijutsu teacher in Encinitas, California.
I'm saying in practice that is not very relevant. A sharp straight blade cuts as effectively as needed as a curved blade of equivalent breadth, edge geometry and mass. Where the true difference between straight vs curved becomes apparent is when you actually view them as weapons to fence with (swordsmanship) rather than viewing them as simple a cutting tool. Sharp straight swords cut tatami, etc just fine. But they have different fencing properties once you learn the techniques and pressure test them through contact sparring.
As someone who has always known Japanese culture but always been somewhat in the dark about many of the customs of the feudal/imperial period, I really appreciate your videos! Thank you! Subscribed!
The curve in katana is a byproduct of the differential hardening process, and is not necessary for drawing the blade. It also does not significantly change the point of balance of the blade, and it definitively does not make it sharper.
not directly sharper, but someone wielding a curved sword vs a straight sword of the same weight and sharpness will find the curved sword to cut more readily from slashing motion than the straight sword.
The curve has absolutely nothing to do with "increased sharpness". "SHARPNESS" is a result of proper sharpening. I know you actually mean "cutting ability", but call it what it is - "Increased Cutting Ability".
THANK YOU! Ugh so frustrating when _anyone_ can cast themselves as experts! I wish all yt creators would be clear when they believe or think something or guess at something, rather than stating it as matter of fact.
I get what you mean, and I might have missed this in the video, but the curve comes from the differential hardening process yes? Would a straight blade not have had the same hardening process and result in a less hard edge that can't hold the edge as well? It's entirely possible your both right and he wasn't precise enough in his phrasing in that statement.
The word "sharpness" may not have been the best choice for what he was explaining, but there's no reason you had to be so rude about it. It was clear what he meant.
Very interesting, enlightening and appealing explanation of a curiosity. I really enjoyed the summary at the end. Rare, but valuable. Arigato gosaimasu.
The true reason for the curve is the quench. Clay is put on the spine of the blade to cool it slower and make it softer. The edge is extremely hard, but if they whole sword was, it would snap. The slower cooling causes the metal to bend on it's own. They are made straight, the quench makes them curved.
Great video I love how a niche topic about weapons lead to a fascinating history lesson and explained the reasoning that influenced the shape of the blade
First of all curve does not increase sharpness, the thing is single edged swords allow greater and smoother transition from the core of the blade to the edge increasing cutting capability, in second the curve minimizes the contact point concentrating more force in a smaller surface that, as well, increseas cutting capability. Cutting Capability=/= Sharpness, sharpness is one factor of many that cutting capability has.
You presented an excellent treatise on the variants of katanas. I might proffer a little more information that might be a possible reason why as well. In the Napoleonic wars, the opposing armies of the British and French used two distinctly different types of swords. the French used straight sabers and they incorporated a fighting style that was two-fold. The French used a parry and thrust style. On the other hand, the British, with their cutlass, utilized a fighting style that put more importance slashing to defeat their opponent. Without going into too much detail as to what the strategy behind their logic was, this anecdote might give perspective. During Napoleonic battles, the French leadership discussed issuing a formal protest against the British for using the cutlass after viewing the horrific wounds the cutlasses were influcting, but French physicians advised the leadership against doing so. They stated that although the Saber wounds French soldiers received looked horrific, many more wounded were surviving. On the other hand, when the human body is pierced by a sword, not only does this cause "decompression of the cabin", but if a vital organ such as the heart or liver are pierced from a blades thrust, it is "game over" and the wounded soldier is more likely to die! This perspective might warrant your further investigating!
This was interesting; I had always been under the impression that the curvature of katana was a side effect of the forging process, and had never been intentional.
@@2adamast it's so when slashing from horseback the blade slides across the target rather than hanging up and slipping out of the rider's hand or pulling the rider off the horse
A really interesting post on this topic. Explained by a friendly person. Videos like these are really fun to watch as a fan of Asian culture and as a sword lover! Best regards from Vienna
your videos are somehow both so incredibly thorough and so incredibly succinct !! you have a real talent for writing and editing. i don't know if you are a native english speaker and i don't want to incorrectly assume, but i noticed you tend to say "formal" where i think you probably mean "former." just wanted to mention in case you weren't aware. thank you so much for your uploads, your content is amazing !!!!
This is fascinating and seems like a really important part of Kendo’s history. Have the straight blades been preserved for kata and solo demonstrations? I have only seen shin-ken demos using the curved blade. I’m sure they had a unique drawing technique has to be developed with them for the battotai to use them. Is that drawing techno taught as well. This blew my mind.
I feel like a straight blade would be much easier to conceal if it was spy/ninja work, and if they were a bit short, they would be perfect for stabbing instead of slicing since slicing is a longer movement, taking more time and room. It is all very interesting and has so much more depth than just a blade shape. Great video!
This is a totally new subject to me, I learned a lot from this video, I'm gonna go read up more on the end of the Edo period now because this all sounds really interesting.
Thanks for your version of the explanation. I learned that a long, narrow piece of metal that is forged on only one side automatically takes on an arch shape. This is the original shape of a single-edged blade as can also be seen in sickles and other prehistoric tools.
I just happened to see the statue of Saigo in a recent trip - I believe they refer to him as the "last samurai". The surrounding park was beautiful, and I enjoyed the museums as well.
Very awesome. The Meiji Restoration is an interesting time period for sure. Lots of intriguing history there that can be traced to Japan as we see it today.
⚔Learn Katana Martial Arts from Anywhere Worldwide with Let’s ask Shogo⚔
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I provide the perfect online lessons for anyone worldwide who wishes to dive into the world of katana martial arts through my style, Kobudo Asayama Ichiden Ryu. I, Shogo, a student myself, will also participate in every lesson and interpret everything in English.
1. No previous martial arts experience is required; you can catch up anytime
2. Every lesson will be recorded and will be available to rewatch anytime
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I bet it was a dream come true to be sponsored by the state for your kendo skills.
Nice to have you back Shogo!
I call him chocko!
One of the fun things about the curved katana is that the curve isn't forged in with the hammer, but created during the quench, through the careful use of the clay through differential hardening. You can find footage online of bladesmiths quenching such a blade in a clear tank and see the curve developing. It's eerie and fascinating.
you said it first and best.
it's not the clay that make the curve, it's how you put the blade in the bath of coolant
It's both the result of the forging process and the selective quenching actually. The blade's curvature is also refined afterwards, using a hot block of copper for example. There are many more variables that influences the blade's curvature. Interestingly during the quenching process the blade curves frontside before going back and settling to the intended shape. You can see this in the fishtank quenching videos you mentionned.
@@UryendelNo , the clay let the blade cool down slower were the clay is thicker . It colls down slower at the back and faster at the edge and this creates the curve .
@@5co756 if that was the case you wouldn't be able to make a straight blade. And the clay doesn't prevent cooling, it prevent heating
Katana blade are drop t in a bassin parallel to the ground with a movement that create the curve. Now if you want a straight, you drop the blade at once in a tube perpendicular to the ground
I love how you not only broke down the reasons for the blades but also the political and social issues so clearly.
Japans eras never cease to amaze me
You're telling me that they aren't ninja blades, but cop blades?!
What is a ninja but a cop undercover.
What if ACAB includes ninjas?
@@Makingnewnamesisdumb reject feudal lord ideology and ninja simping!
@@MasterOfBaiter What do cops have to do with assassins?
@@vids595 ninja were not really assassins in history they were more intelligence gatherers and a lot of them were actually samurai. Literal undercover officers of the state.
I've been playing Like a Dragon: Isshin! lately and have been learning all about the Shinsengumi and the Meiji period. Thank you for providing more information about this very tumultuous and interesting point in Japan's history. And welcome back Shogo!
ten years in the dungeon
Just a small nit-pick about the purpose of the curve. Although said curve DOES make for a better cutting/slashing implement vs a straight blade, it is NOT actually any sharper (assuming equal craftsmanship). The improved cutting dynamic has to do with the relationship between the blade shape and the natural arc that a human body will produce when swinging it. Think leverage, surface area, and ergonomics rather than inherent mechanical sharpness.
Great video! Super interesting!
Correct.
This is actually not true. a light curve does not impact cutting capacity of a sword directly in most cases, the only impact is in the fact that it makes it easier to feel the edge alignment.
Curves do (stronger curves more) increase the ability to draw cut, but draw cuts are very uncommon in Kenjitsu or Iaido and are only common (as far as I know) in fighting styles with very curved sabres.
@@deltrex on top of this, a curved blade also increases the pressure at the edge, the smaller the contact area, the better the cut, it's why scissors have their distinctive shape, rather than just clamping 2 parallel blades together, and why axes usually have curved edges.
I don't trust you. What's your source?
@@deltrex
Drawing cuts occur whenever a blade moves in an arc. Swing a blade, creates a draw cut, more curve, more draw cut.
Arigatou gozaimasu, Shogo-San! Your videos are always helpful!
As an overseas kendoka I was super surpried to learn so much about it in a non kendo video. It also funny that kendo was used both by the Shogunate in the form of the Shinsengumi and by the Government with the Battoutai.
"We may have our differences but we agree on one thing. Kendo wins wars"
I cannot agree. Shinsegumi used classic gekiken (free sparring), look at Tenen rishin ryu. Yes, they used similar gear, it is ancestor of kendo, but whole gekiken is ancestor of kendo, which is sport with rules, and gekiken is training method. Yes, i see videos with "old school kendo", but thats practicaly gekiken before rules was setted.
@@23Disciple Gekiken was a gamification of the uchikomi keiko of the jikishinkage ryu, which was first made into a sport within the Nakanishi-ha itto ryu and popularised by the 14th headmaster of jikishinkage ryu Sakakibara Kinkichi, who founded the Gekken Kogyo. Uchikomi keiko was a corrective measure for "dead" kata, gekiken since renamed to kendo was always an extracurricular sport.
Free sparring is a very modern concept, the people of that time would have had duels, the purpose of which was to prove their system and skill. The word for a duel between students of different schools is taryu jiai not gekiken.
Nobody does it better than Shogo! 👍🏽
I have always been fascinated by Japan it's people it's culture it's history I've got a lot of books on the subject
Your channel has greatly expanded my knowledge thank you
It's its. Not it's
Shogo remains my favorite channel in regards to Japanese culture and understanding. Love your videos.
This was indispensably informative, Shogo-san! This clears up a lot of my own confusion and misconceptions about the change in blade styles during the Meiji Restoration Period.
It's been a while. Glad to see you back!
The curve also increases the length of the cutting edge without increasing the overall length of the sword, making it slightly more convenient for carrying and close fighting.
That is covered both by the aids in cutting/sharpness segment, and the balance and drawing segments he went over. So he covered those points.
I'd say the metal becomes stronger, just as a bow that can project energy at a point with the help of curvature.
None of those things make sense. What's the advantage in having more cutting edge without more reach?
The metal definitely doesn't become stronger because it's curved. There's absolutely no principle that would make that happen, unless the sword was extremely curved, like an arch supporting the weight of the wall above it. The curve in a katana is way too slight to have that effect. And what does it have to do with a bow? A bow bends to store energy, which is then released into an arrow, which has a point. That's the only sense the bow uses curvature to project energy at a point, but none of those mechanics are in common with the katana.
The only advantage to the curve is that when you swing a sword, you move it in an arc, and a curved blade more readily follows the arc as you draw it across the thing you're cutting, therefore making the cut easier. Also if you're hitting a flat surface, less of the blade comes in contact at a time, so it exerts higher pressure. But you never hit a flat surface with a sword, so that doesn't really matter. It matters when cutting veggies on a flat cutting board.
@@mrkiky You do increase the cutting length. Geometry, dude.
@@ericthompson3982 you don't increase *effective* cutting length - cutting length that you can use. Why? Because the curve retreats towards you! This reduces the extra reach you're technically given.
You're absolutely right about geometry, but you can't suddenly "straighten the sword" during a fight to make effective use of that extra cutting length.
A straight-blade with a couple inches LESS BLADE would have the same *effective* cutting length as a curved sword with a couple inches more blade, if you follow what I'm saying
This video makes me want to go and watch Rurouni Kenshin again. Great content as always. And welcome back!
Same! (Particularly the live action films) :D
I still remember Sakamoto Ryoma had a straight sword called Mutsunokami Yoshiyuki. I hope I'm right because I've been playing Touken Ranbu for a long time.
Your videos are the best & most enjoyable! Don’t mind the less frequency at all, if anything it makes me even happier to see a new one. ❤
A very informative video. Love hearing about Japanese history (along with history of weapons in general) and hope to some day visit. You've just gotten another subscriber from me!
Thanks Shogo! Wonderful presentation on the straight katana. ❤
I think you are right about the 'ninja sword' not to mention the whole ninja panoply. Movies aside, a spy/scout and a commando are very different things. If a spy does his job right, no violence ever happens; he or she blends in, does nothing suspicious and sticks to his story. Much safer if he isn't armed at all. Most special 'gadgets' if any are reserved for the most dangerous parts, which would rarely include assassination (e.g., Operation Valkyrie) but more commonly communication with his handlers. Ninja commandos if they existed, no doubt trained for night raids and wore camouflage, but their weapons and gear was likely not otherwise different.
Love this video ❤ I'm glad you're back. 👍
Yay Shogo is back! It was very informative thank you!
I love the presentation style of this channel and Seki Sensei’s. Showing me a table of contents seems like it would steal the video’s thunder, but in reality, it usually piques my interest, while setting an expectation of what’s to come. It’s remarkably relaxing.
*sigh* No.
The curve came about because smiths in the 8th century started making blades with a low Carbon steel core so that there would be fewer broken Chokuto in battle... and they discovered that that new composition caused the blade to curve in the quench, creating the Tachi. Straight Chokuto and curved Tachi of that period were identical in every way except for the composition that caused the curve. The curve wasn't the goal in the beginning: it was a happy accident that they found had advantages for horseback and draw, so it replaced the Chokuto, but the reason for the change in composition was to have blades whose spine would bend without breaking, NOT to have a curved blade. And the later era policemen's blades were straight because they were made fast and cheap with one grade of steel instead of two or more, so the differential hardening from the clay would still give a hamon but the blade would not curve in the quench, because the core steel wasn't a different Carbon content than the edge steel.
Loved this one.
Also, with the utter respect, and also revealing my venerable age - Saigo Takamori gives me a sort of Golgo vibe.
golgo 13?
@@WhuDhat YES!
This is really cool because so many blade "experts" have said that the straight blade katana is a product of Hollywood.
Awesome video as always Shogo. Shogo I always look forward to watching your videos on all kinds of topics about Japanese 🇯🇵 culture keep up the great work.
It's really awsome to watch your videos again.Also looking forward for more Kyoto family vlogs.
The Return of the King
As always, really interesting. One thing though. The katana or the odachi were curved not just to be safely drawn on horseback, as you say, but to deliver deeper cuts while moving. One of the reasons why the monouchi was the sharpest part of the blade, for the reach.
no, they were curved so they wouldnt hang up and pull out of the rider's hand when slashing at a gallop, curved makes blade slide across target rather than bury or grab
All I want is for you to continue creating these videos and including as much information as you possibly can! It is always exciting to learn something new, especially from someone knowledgeable about the topic. Thank you very much. ☺️
Found my new favorite channel on yt. Love Japan and Japanese History!
Curves do nothing for balance and certainly don't increase sharpness.
1: Balance is impacted by the profile taper and distal taper of a blade and also by the weight of the handle in relation to the blade, a curve does nothing to make a sword feel lighter, especially a light curve as it is on the Katana. It does however make you feel the edge alignment better.
2: Sharpness is a combination of edge profile (or thinness) and level of polishing. A curve does not make anything sharper.
The curve does mechanically help in cutting. Think of it as a kinetic energy transfer, with a straight edge if you hit something the entire edge makes contact with the object at the same time, imparting its kinetic energy evenly across the object's surface, cutting it in the process but diffusing the energy a cross a larger area. Now consider the curve of the sword. You are still imparting the same kinetic energy as long as the are the same lenght and weight right? Yes but the difference is that the moment the curved sword makes contact only a very small part of the edge makes contact first concentrating the kinetic energy into a verty small point. This increases the cutting power dramatically despite both examples involving the same potential kinetic energy.
@@alexisrivera200xable that would only be true if the object you are cutting is flat and the edge hits it perfetly perpendicular. In reality almost nothing you'd want to cut with a sword is flat and also any area on a Katana that is about the length of a hand (so the size of a target) will seem basically streight because the curve is so small it is almost imperceivable. And most targets are at least a bit soft and elastic taking away even the last bit of theoretical advantage such a slight curve may have.
OMG I’ve NEVER gotten so bored with a “sword” video so fast..
As a lifelong kendo/iado student, I truly appreciate your reverence for the katana and the various disciplines that have evolved over the passage of years.
Thanks for your explanations on non-curved Katanas.
Well actually, regardless of the "katana" topic, you are perpetuating a myth of curvature making it sharper. Yes curvature do lower a proportion of the blade contact length which in theory should multiply the force. But It works only with much stronger curves. With something like Shamshir blades. And still the test shows negligible effectiveness compared to straight blades. According to scientific experimental data, curve of the katana blade does literally nothing to make it perform better in term of cutting ability.
It also helps with aligning the blade during a cut, which also perpetuates that myth. It makes it easier for people to use even without as much training with blade alignment.
Which tests? I would like to read them
swords with stronger curvature were a thing, but afaik, not common among the katana you're probably thinking about since those are a result of sword regulation during the 1600s or 1700s?
I've also heard this but one thing a lot of people often miss when talking about it is that fighting techniques make essential to the shape of the Katana. They are easier to draw with the curvature for example. This doesn't make it superior in cutting power or anything and indeed they are harder to handle than a long sword for example.
This was very informative and it is so nice to see videos from you again!
It's been widely reported and proven that the curvature was as a result of the dissimilar metals used in the production process, for the back and the cutting edge, and how they contracted differently when quenched. The cutting edge was the primary focus, and then the balance between flexibility and rigidity.
The easier draw, better cutting, etc, was secondary benefits; and the became the reasons why the production process stayed.
This is why I love studying Japanese history, it's so intricate. Everytime I think I know everything about the Bakkamatsu, I find something like this.
Video starts at 1:30
I am so grateful to live in a time when I can get this knowledge from my room, thanks Shogo!!!
I thought the curve in a katana was due to the iron spine of the blade shrinking more in quenching than the steel core. how then do you prevent this to make a straight blade?
You can just make a counter curve in the blade prior to quenching, instead of starting with it straight. That way, when you quench, the differential shrinkage reverses the counter curve to end up with a straight blade,
Glad to see you back Shogo.
A curved blade doesn’t make it “sharper”. Rather, it assists in slashing ability as a separate factor from sharpness. Sharpness is simply the quality of thinness in a blade.
@@LimaXIII huh? My comment has nothing to do with history or culture 🤣. It’s the English language. How ironic
Your a kind and humble person, sharing your culture... I have nothing but respect fot this!! :)
Does the forging technique and fact that katana are forged straight and curve when they're quenched have anything to do with it as well?
No, that's a misunderstanding; they are forged curved. The quench does briefly cause a reverse curve, but it comes back to the same curvature when the temperature equalizes.
This period would be one where the ancient techniques were coexisting with modern Western metallurgy, so it's possible swords could have been used that were made from cheap imported steel billets rather than tamahagane, which is easier to track and control. IIRC part of the reason for the curve is a hedge against impurities in the blade, you have to slice along the length of the blade rather cut or hack with one point of contact, and this wouldn't be needed in a more uniform, industrial product, so they were free to match the form of the swords used in kendo, though the need to hedge against impurities had long passed by this point in history
So, yes, especially as the differential quenching using clay was a specialised technique, the fact that curved katana needed specialised techniques to both make and use and straight ones less so, it was easier to supply a rebellion with straight blades, similar to how large European armies generally used straight blades and curved blades where for specialists or officers. Thinking about it, this might also be why ninjato(if they actually existed and weren't, perhaps, inspired by the Battotai) were straight. A curved katana with a hamon might as well be fingerprinted, so connections could be made to who made it, and then to who might have bought it, whereas a straight blade with a simple handle is essentially anonymous and easier to discard during an escape and replace
Thanks for being back some content!!!!
It's a fascinating thing to consider as a western fencer and Blacksmith used to wielding mostly straight blade swords. The simplest answer is that they are FAR easier for new troops to learn quickly, as they can focus on the thrust in a fight. While Tachi and Katana are powerful cutting weapons they are VERY difficult to thrust with powerfully. I am NOT saying they can't or that practiced wielders are unable to thrust effectively, just that it's far more difficult for someone used to a straight weapon to do. I have zero kenjutsu training, and only a minimal number of times doing kendo, but I did fence in college and then got into Hema (SCA back then) about 20 years ago. I have cut and handled Katana many times too so I'm only offering an account of the experience of going from an arming sword, jian, and long sword. Nothing I'm saying is to contradict or overrule the information presented here.
My personal experience is that straight and lightly curved sabers thrust about the same, katana are usually pretty lightly curved so I doubt it makes much difference.
@@atom8248 I found it significantly harder to be accurate and to pierce the same target to nearly the same depth (stacked tatami mats or other materials). It might be much easier for anyone who does hema sabre or another sport/MA that uses swords with more arc. I do feel a difference with some Dao that have a straight lower ⅓ to ½ and keep most of the mass centered on the grip. I notice the weight of Katana/tachi that's behind my hands throwing me off, or at least that's the best I can describe it. It's possible I've only handled Katana on the longer more curved side, closer to Tachi than a late Edo period blade would be as well, I've seen a number of blades in museums as well that would tend to be older and original made as Tachi so my impression of them may also be skewed to the ones I used being representative of Katana generally?
I am thankful to have watched this! Your knowledge of history is something I would like to see more of. I will be checking out stuff from time to time. Well done!
The best explanation I've heard for a curved blade, is that when slashing, it concentrates force on a smaller area than a straight blade. Hence, it's better for slashing cuts.
In my view, that is not entirely true. Straight blades can cut just as well in open spaces, and the katana only has a mild curve so it doesn't really contribute to this supposed cutting "power".
What is more plausible is when you start looking at actual fencing techniques and systems. In Historical European fencing, straight swords and curved swords utilize different techniques to accentuate their strengths.
Broadly speaking, straight bladed swords (longsword, rapier, smallsword, etc) use 'long distance fencing' strategies to take advantage of the sword's tip to hew and thrust. The longer your straight sword, the further distance your strike can hit.
Curved bladed swords (sabers, cutlass, etc) use 'short distance fencing' strategies to take advantage of the sword's ability to slash at short distances. That is the real purpose of the curve. Imagine a sword fight happening in an elevator where there isn't a lot of room to fight. A curved sword can slash using lateral movements, whereas a straight sword is more restricted in its movements.
Curved swords are more adaptable to close-distance fight situations, such as indoors. Katana is probably curved for this reason. Straight swords have a reach advantage in wider-distance fight situations. That's why it's very hard to fight against a longsword or rapier using a curved sword. It's not impossible to win, but it definitely feels like an uphill battle for the curved sword wielder. I surmise that the Japanese wielders of straight katanas realised this advantage.
@@kissing88 I'm thinking physics. In a slash, the entire straight sword makes contact with the target while only a portion of the curved sword makes contact. Same force over a smaller area for the curved sword means more pressure. I recall the explanation coming from James Williams, the aikijutsu teacher in Encinitas, California.
I'm saying in practice that is not very relevant. A sharp straight blade cuts as effectively as needed as a curved blade of equivalent breadth, edge geometry and mass. Where the true difference between straight vs curved becomes apparent is when you actually view them as weapons to fence with (swordsmanship) rather than viewing them as simple a cutting tool. Sharp straight swords cut tatami, etc just fine. But they have different fencing properties once you learn the techniques and pressure test them through contact sparring.
@@kissing88 Thanks for the interesting discussion.
I think it is a target size thing. If you have to fruit ninja a 200-800 pound pumpkin or equivalent, a curved blade will flow better
As someone who has always known Japanese culture but always been somewhat in the dark about many of the customs of the feudal/imperial period, I really appreciate your videos! Thank you! Subscribed!
Video after a long time Shogo love from India 🇮🇳❤️🇯🇵
Battoutai?! that's so badass! This is a very informative explanation. It is amazing how far kendo has travelled across the world.
The curve in katana is a byproduct of the differential hardening process, and is not necessary for drawing the blade. It also does not significantly change the point of balance of the blade, and it definitively does not make it sharper.
not directly sharper, but someone wielding a curved sword vs a straight sword of the same weight and sharpness will find the curved sword to cut more readily from slashing motion than the straight sword.
it does occur during heat treatment, but the curvature is decided upon by the smith through shaping before quenching.
This was a great history lesson!!
The curve has absolutely nothing to do with "increased sharpness". "SHARPNESS" is a result of proper sharpening. I know you actually mean "cutting ability", but call it what it is - "Increased Cutting Ability".
THANK YOU! Ugh so frustrating when _anyone_ can cast themselves as experts!
I wish all yt creators would be clear when they believe or think something or guess at something, rather than stating it as matter of fact.
I get what you mean, and I might have missed this in the video, but the curve comes from the differential hardening process yes? Would a straight blade not have had the same hardening process and result in a less hard edge that can't hold the edge as well? It's entirely possible your both right and he wasn't precise enough in his phrasing in that statement.
@@neisan92 Didn't see it that way, but Indeed, trying to keep the blade straight would make it less sharp.
Sharpness is ability to cut. Curve increases ability to cut.
The word "sharpness" may not have been the best choice for what he was explaining, but there's no reason you had to be so rude about it. It was clear what he meant.
Thank you for posting, Shogo-san. You videos are always entertaining and very educational.
"Curved Sword only belongs to Hammerfell" - Whiterun Guard
Very interesting, enlightening and appealing explanation of a curiosity. I really enjoyed the summary at the end. Rare, but valuable. Arigato gosaimasu.
Thank you for mentioning Shinsengumi! It kinda makes me happy when someone mentions them^^
So a curved sword should be a symbol of elitism while straight swords and short swords should be a symbol of equality.
peasentry
@@nikolaygeraksiev5239 democratization of violence.
Fantastic video! You shed some light the popularity kendo and the use of straight shinai for sword practice. I have to admit, Im pleasantly stunned.
The true reason for the curve is the quench. Clay is put on the spine of the blade to cool it slower and make it softer. The edge is extremely hard, but if they whole sword was, it would snap. The slower cooling causes the metal to bend on it's own. They are made straight, the quench makes them curved.
Great video I love how a niche topic about weapons lead to a fascinating history lesson and explained the reasoning that influenced the shape of the blade
First of all curve does not increase sharpness, the thing is single edged swords allow greater and smoother transition from the core of the blade to the edge increasing cutting capability, in second the curve minimizes the contact point concentrating more force in a smaller surface that, as well, increseas cutting capability. Cutting Capability=/= Sharpness, sharpness is one factor of many that cutting capability has.
I'm enjoying our Chanel Shogo and thank you for showing us the great Katanas
Loved this history lesson about Japan. Enjoyed learning about the different katana swords.
I really, really, like this format. It is an interesting story followed by a review. This is professional quality instructional video.
You presented an excellent treatise on the variants of katanas. I might proffer a little more information that might be a possible reason why as well. In the Napoleonic wars, the opposing armies of the British and French used two distinctly different types of swords. the French used straight sabers and they incorporated a fighting style that was two-fold. The French used a parry and thrust style. On the other hand, the British, with their cutlass, utilized a fighting style that put more importance slashing to defeat their opponent. Without going into too much detail as to what the strategy behind their logic was, this anecdote might give perspective. During Napoleonic battles, the French leadership discussed issuing a formal protest against the British for using the cutlass after viewing the horrific wounds the cutlasses were influcting, but French physicians advised the leadership against doing so. They stated that although the Saber wounds French soldiers received looked horrific, many more wounded were surviving. On the other hand, when the human body is pierced by a sword, not only does this cause "decompression of the cabin", but if a vital organ such as the heart or liver are pierced from a blades thrust, it is "game over" and the wounded soldier is more likely to die! This perspective might warrant your further investigating!
This was interesting; I had always been under the impression that the curvature of katana was a side effect of the forging process, and had never been intentional.
TBH, I think that's closer to the truth (at least in the beginning).
All over the world most sabers are curved. I think it is by choice
@@2adamast it's so when slashing from horseback the blade slides across the target rather than hanging up and slipping out of the rider's hand or pulling the rider off the horse
Beautiful katanas in the back, great informative video!
Shogo, you have taught me so much. Many thanks.
A really interesting post on this topic. Explained by a friendly person. Videos like these are really fun to watch as a fan of Asian culture and as a sword lover!
Best regards from Vienna
Very interesting history, i like it 👍🏽
Just want to say, I love your videos and have always been fascinated by Japanese culture.. love it.. wish I could visit someday
your editor is doing an amazing job btw
Nice to see you back to doing your own channel a bit too.
Happy to see a video!! ❤❤
your videos are somehow both so incredibly thorough and so incredibly succinct !! you have a real talent for writing and editing. i don't know if you are a native english speaker and i don't want to incorrectly assume, but i noticed you tend to say "formal" where i think you probably mean "former." just wanted to mention in case you weren't aware. thank you so much for your uploads, your content is amazing !!!!
This is fascinating and seems like a really important part of Kendo’s history. Have the straight blades been preserved for kata and solo demonstrations? I have only seen shin-ken demos using the curved blade. I’m sure they had a unique drawing technique has to be developed with them for the battotai to use them. Is that drawing techno taught as well. This blew my mind.
Thank you for the teachings.. I'm looking forward to learning more
I feel like a straight blade would be much easier to conceal if it was spy/ninja work, and if they were a bit short, they would be perfect for stabbing instead of slicing since slicing is a longer movement, taking more time and room.
It is all very interesting and has so much more depth than just a blade shape. Great video!
I'd love to see a video about the history of the Shinsengumi, as well as other factions from that era.
Welcome back shogo 🎉 and love the new looks 😊
Great video! So glad to have you back and always love your well explained format.
This is a totally new subject to me, I learned a lot from this video, I'm gonna go read up more on the end of the Edo period now because this all sounds really interesting.
Very interesting!!! Thank you for that video (ありがとう)! ☺
Thanks for your version of the explanation. I learned that a long, narrow piece of metal that is forged on only one side automatically takes on an arch shape. This is the original shape of a single-edged blade as can also be seen in sickles and other prehistoric tools.
But a scythe curves inward and a sabre curves outward,
Welcome back! Thanks for this amazing lesson
Fascinating martial arts and Japanese history lesson! 👏
I just happened to see the statue of Saigo in a recent trip - I believe they refer to him as the "last samurai". The surrounding park was beautiful, and I enjoyed the museums as well.
Very awesome. The Meiji Restoration is an interesting time period for sure. Lots of intriguing history there that can be traced to Japan as we see it today.
Really interesting video! It gave me all kinds of flashbacks to watching Kenshin like 20 years ago. Insane it’s been that long, wow
Very informative. Thank you.
Fasinating, all these years and I hadn't thought about it... I didn't even know a police force used non-curved katana. This is why we need Shogo.
Thank you for this and welcome back! 😉
Thank you for your videos.
Another amazing video, Shogo! Love the mix of martial arts and history. :)