Extreme Sudoku: Wings, Skyscrapers & Empty Rectangles
ฝัง
- เผยแพร่เมื่อ 27 ก.ย. 2024
- Simon takes a look at this "extreme" rated puzzle requested by one of our viewers. As usual, these solves allow us to showcase some exotic techniques. This time we have x-wings, y-wings, skyscrapers and empty rectangles!!
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#Sudoku
#crypticcracking
#commitsudoku
#xwing
#skyscraper
Possibly one of the most instructional videos on the channel.
X-wings, Y-wings, Skyscrapers and Empty Rectangles all shown and explained in clear terms with visual aids besides.
Glorious.
That's one reason I love the channel, I'm learning all these tricks.
9:00 skyscraper
12:40 x wing
16:45 empty rectangle
notchinthebedpost 24:25 y wing
@@preciousghouls 25:50 final sky scraper
I would also note that he changes notations at around 10:30. He recognized the skyscraper at 9:00 but not using the 'standard' notation. It took me a while to realize that often the skyscraper, xwind, empty rectangle can be hard to see with the standard notation.
12:31 naked triple in row 8, 1-7-9; you can resolve the 5 in two cells.
15:01 "I feel like I'm missing something here." Shouting at the screen "The five in the 8th row!!!"
I know. Sometimes I imagine if someone is looking over my shoulder and they see something obvious and I don't see it.
Beautiful! Do enjoy the logic and the step-by-step explanation using empty rectangles and skyscrapers!!!
who's here in 2021 smiling at Simon apologising for a 27 minute solve.
2022 :)
08/02/2022 :))
2022 as well
Just watching to try and get my head around empty rectangles and being so impressed by how far the presentation and the software has come. :-)
2023 hello
Really appreciated the logic at the end rather than the 'brute force' so thank you for that. Not that I have anything against the speed solving techniques, just a fan of the logic more.
The additional drawings really help demonstrate the difficult concepts. Thanks for continuing to add them!
This video taught me more than most others combined. Taking the time to explain not just the logic of a wing, skyscraper etc. but how to find them helped immensely. A well chosen puzzle for the tactics too as the wings, skyscrapers and empty rectangles abound. I ended up solving it using several different combos than he did
Thanks so much for taking the time to explain the many techniques that you use. I am really learning a lot from you and from these videos.
New to sudoku world and I'm mad I didn't learn sooner... sudoku is great. Thanks for explaining in a way my beginner's mind could understand. 🙏🏽❤️
That was one roller-coster ride of logic.. Great work as always..
Don't worry about the length of the video, the content is good and worth it.
Please more technique videos, I learnt a lot from this. Bought your app and it is so much fun
Huge help. Thanks. I couldn't understand how the the hints worked till you explained it so patiently!
Thank you for the excellent explanations! I appreciate this a lot more than brute force solving and I really don't mind you missing an "obvious" insertion here or there... to me, it's much more helpful to understand the logic of the advanced techniques and this video delivered in spades! :-)
Great explanations! This really helped things click for me. Thanks for showing so much in one video and trying to find those patterns rather than just solving
When you did the empty rectangle, I had found the same 2 by using skyscraper on the 34/39 pairs.
There are some good tips that I've learned. But I was screaming at the screen because of that 179 triplet in row 8 that made R8C6 a 5.
or that he didn't pencil in r7c6 🙈
Yes, this happens in every video. Simon is better than most at using logic to make breakthroughs whenever he has hit a stop in the puzzle, but when it comes to the simpler things, such as tidying up his pencil marks and scanning the grid, then he performs much worse, possibly worse than the average person. Not that I am hating, though. It can be irritating to watch for those moments, but the videos are still entertaining enough for me to always come back for more.
He even writes in all the candidates in r8 and and doesn't notice the 5 can only be in one cell :D
Even when working at this ‘slower’ pace for us, he’s constantly scanning and calculating the best next move.
It’s easier for us as viewers to spot the more obvious things while we watch him work on the harder ones.
For me, that was the best not the worst way. The skyscraper technique, Y wing and and rectangle techniques are so much more intriguing than simpler logic. A lot of us who want to crack the hardest puzzles love being shown the harder logic tricks
I got stuck on this puzzle with the exact arrangement of numbers you had just before explaining the "empty rectangle" logic around the 16:30 mark.
That is a clever trick. I'll try to remember it. Thanks for the video!
Me too!
Going through these videos has allowed me to solve expert level Sudoku on my app without help half the time now. I used to have to hit the help button often. Easy thru Hard are solvable without help, but the Expert level ones are tricky. I am finally making progress.
As someone who's only recently started playing, I greatly enjoy the videos. The in-depth explanation is very helpful!
Hey, love the videoss! Just a thought I saw someone mention before which I agree with big. You should get a dedicated mic for these. I'm a sound engineer, and I would recommend the Blue Yeti USB mic. Cheap and robust and has great clarity for the price :)
Sound Crank For some reason my blue yeti isn't working at all with my laptop. I've tried it with another computer. It works with that one, but on my laptop the audio comes through all chopped up, if it's picked up at all. Have you dealt with this before?
I was hoping a sound engineer would know that the Blue Yeti isn't that great of an option. Rode or something along it would be a far superior option, even a cheaper microphone if it has XLR :)
@@WwortelHD Honestly, the difference is negligible for this usecase scenario. For the cost of one, it's rated the number one podcast mic for a reason. Personally, I use a blue baby bottle, but not everyone has $360 spare laying around for a good mic lol
My gosh. I thought I could solve it!!! The techniques you have used are quite complicated. I can say I lower my level to medium and a little high sudoku solver. The y-wing and the skyscraper and empty rectangles techniques are very hard to understand and to spot on
21 minutes in and I realized the video is tagged with #commitsudoku. Holy smokes, Simon.
what does that even mean?
@@aseloss if you google image search commit sudoku, it will show a drawing of a Japanese man committing seppuku, except it is a sudoku board cut into their chest.
Confusing the word Sudoku with Seppuku became an internet meme
@@aseloss The Japanese word "seppuku" is the name of a particular procedure by which samurai historically would commit suicide if given the orders to do so or of their own will, which is done by stabbing a katana into the middle of their torso. Another name you may see for this is the word "harakiri."
For reasons I have not bothered to research, people on social media started using the word "sudoku" instead of the word "seppuku" when talking about committing suicide by the process explained above. Thus, in meme culture nowadays, people associate the phrase "commit sudoku" with the act of committing suicide. This is why the OP was shocked at seeing "commit sudoku" as a tag for the video.
Dont apologize for taking extra long time. Some of us are learning the logic instead of brute force
I now have a headache, but it was worth it. Had to keep pausing and rewinding to fully understand the logic, but I eventually got it. Great tutorial!
I'm not sure if this would have sped up the process, but at 12:30 there was also a 79 -179 - 179 triple in R8 along with the 43-43 matching pair which would give you the 5 in R8C6 earlier in the puzzle...
Great video, I am finally getting the empty triangle.
So fun watching you ending the puzzle! More of this please!
Newbie, so I love that you go slowly, I can keep up with you that way. Thank you.
This might be my favourite video you've done!
Highly helpful. Thanks
Brilliant, these videos have helped me no end. Thanks 👍
That was great. Wonderful logic...much better than guess-and-error technique.
Thank you for not guessing! This was really hard but I like that logic was always used to one day I will be able to spot these triangles and wings myself.
Glad you talked through these techniques in this video. A lot of them are things I've recognised as useful when doing solves but not being able to say why are take advantage of the patterns like you did here. Now that I'm more conscious of how to utilise such restrictions, it should improve my solving. Thank you :)
Very well done! I have found a love for Sudoku and I have gotten pretty good at solving expert level puzzles but want to be bettter so decided to watch your videos. What’s weird is I have been using some of these techniques and not even realizing that they had a name. The skyscraper still has me a bit confused. Also by watching your videos I now know how it feels to see something and be yelling at the video. After you locked in the 3/4 in row 8 I solved the 5’s and the rest of the video I was trying to tell you “You’re missing the 5’s!” 😂
If you get your videos in between 20 and 30 minutes, you are doing great. I enjoy watching the logic being played out.
Beautiful
16:45 there is also an empty rectangle of 3s in the top three rows. This would eliminate the 3 in the bottom right of the first block and the 3 in the bottom middle of the third block.
THank you learned y wing, skyscraper and empty rectangle for the first time!
this puzzle was insane! so many logic ways of doing this that i can't. this one scared me
At 23:00 I see a skycraper with 1s in rows 4 and 8. This eliminates the possibility for 1 in row 6 column 4, which then resolves the puzzle. :-)
23:43 He goes into empty rectangle, but an easier logic principle is skyscraper on the ones in row 4 and row 8
Yes, but this would have made the video less instructive, which I believe is actually the point of the video.
Great work. The elimination of snyder notation to avoid too much clutter. Does this limit your solving ablilty in any way.
What a great solve, down to the last logic line to crack it!
Interestingly at 16:30 I used a skyscraper to eliminate the 3 candidate from R3C3.
The skyscraper is R18C7 for the base and R1C2 + R8C3 as the roof.
This makes the same elimination as your empty rectangle. =)
Wow, I'm new to Sudoku so this was a lot to take in. Two things I want to learn more about is the hidden singles and the concept of "what cell sees two other cells".
A cell sees all of the cells in the column, all of the cells in the row, and [which is important] all of the cells in the same block.
Great video!The techniques you've shown are really helpful!
Feel proud that I got 2 of the fives before he did just before he blew my mind with the empty rectangle shenanigans
I appreciate the explanation of skyscrapers and empty rectangles, they aren't patterns I'm good at identifying or using to solve my puzzles.
What sort of sorcery is this? I feel like I've unlocked a secret knowledge. Thank you for showing this
"My brain's not clever enough to do it quickly," he says. Well, my brain's not clever enough to do it AT ALL!
wow really enjoyed that one. thanks Simon
When you demonstrated the first empty rectangle, there was also an x-wing available in columns 2 & 8 on threes.
Easier to spot also and it gives you the same 2 in block 1
Amazing video! Thanks and keep up The good work!
Great video! I'm newer to the channel and it was definitely helpful!
I solved it using brute force after reaching a critical point, which is not entirely satisfying... this video showed me what to do... with a lot more practicing I will be able to do it on my own I guess.... thanks a lot!!!
Persons reading the comments. Do you consider this BRUTE FORCE? At 22:45 he had penciled in all of the remaining boxes. He even comments he doesn't want to use 'Brute force' to finish the puzzle. He then goes on to find the empty rectangle and Y wing etc. I agree this is not a use of brute force since it still used logic even though all of the pencils were in. To me, brute force would be to guess a value on a pair and see if it works. THOUGHTS?
Glad to know I'm not the only one who misses obvious triples for over 20 minutes.
9:10 Maybe I'm stupid, but I see three options to place the 9s in this skyscraper. The two X-wing options that you explain, but the third option would be a 3 and a 4 in column 7, and both 9s are on the left side of the skyscraper, which they can be, because they are not in the same box and not in the same column. And there's plenty of other rows in column 7, where the 9 can be, or not? Of course the logic for the cell in row 3, column 3 is still the same: It can not be a 9, especially when both 9s are on the left side of the skyscraper. It would be like a double fail.
15:00 There is a skyscraper with the 3s in rows 1 and 8. (Similar to the earlier skyscraper with the 9's in rows 1 and 4). Both cases together remove 9 and 3 from r3c3, which now must be a 2.
You (Simon) get to the same result looking at 3s with the empty rectangle in box 7 and the 2 restricted 3s in column 8. Surprisingly you could also look at the empty rectangle in box 3, which connects with the 34 pair in row 8. Again, also prooving that r3c3 can't be 3. Summarized: The 3 in r3c3 really had no chance.
It would be nice if you added the links to the web app, to the old videos so we can try solve it before the video. :)
That was hard but once you boil it down, in the end row 7 & 8 can only lack a 7 1 9 which means colum 7 8 on row 9 can only be a 1 or a 6 and that unlocks the whole thing.
Skyscrapper : 8:40 & 25:50
Empty rectangle : 16:25 & 23:15
Y-wing : 24:25
yeah, i learned a lot from this
i still suck tho, need practive
i learn much, thanks!
You know what, good call on the new mike :-).
Try using right click to switch between "BIG" and "LITTLE". Might work faster for you as it does for me.
I got lost after the skyscraper entered!
I found two scyscrapers with 4s and 3s and a bend quadruble of 1-4-7-9 that solved the rest. For each to their own I guess.
Thank you
"Which is the most frustrating thing when doing these live solves, because...."
...because it leads to dead air? 😉
12:05: the 3/4 pair restricts 5 to row 7 / col 7.
The first thing I look for is a way to solve it along with you in a different window. I don't know how to create a suduko using your software and I didn't see a link for one already made here. I'm not smart enough to remember all of the techniques until I have actually run it a couple of times.
18:34 can some explain to me why square 3 in column 3 can’t be a nine or why the square to the left of it can’t be a two
Could you guys please include the links to these puzzles. Would be nice to give it a try first before watching
I dont think there is a link, i think he just copied down the sudoku that was emailed to him into whatever program he uses. You could instead copy it down yourself on paper or in a program if you wanted to try it. Its kind of annoying, but im pretty sure thats the only way to try the puzzle.
Simon is using Duncan's sudoku on Windows. Download it for free and you can pause the video at the start, enter the puzzle and have a go yourself before you see the solution
That was neat.
Thank you Sir Simon for your beautiful content and explanations. I have a question :can we consideration C1 -C4..skyscraper for 7..and he driving in c1r6=7 ... ? Please answer me.
what are all the differences between a skyscraper and an x wing?
After the skyscraper at 10:19 could a 9 be put directly into C1R8?
TIA
18:40 could you not also do that logic with a skyscraper with the 3 9 in row 1 and the 4 3 in row 8? i'm new to these kind of advanced sudokus so sorry if im wrong lol
I learned 2 new things: the Y and skyscrapper :) thank youu. Still dont understand the empty rectangle though
After watching a few of these I _think_ I'm starting to get it. It's actually similar to a wing pattern, except that the pivotal vertex is an entire box, instead of a number pair.
Essentially, you find a box with a number in it that is restricted to a single row and column, and see if that number interacts in a rectangular chain/loop with other partially-resolved numbers (usually an x-wing-like pair pattern). If it's a true empty rectangle, then running the logic in either direction will result in the same elimination -in the originating box- (edit: actually anywhere in the chain, as in this video's example).
It seems that they're really tough to spot, and the eliminations can be a bit complex, but the pattern itself is understandable enough.
8:03 Empty rectangle in block 3 can reveal R3C3 is a 2
that was great!
12:30 R8 1-7-9 resolve the 5s in R7, R8
I was literally screaming at my phone for 10 minutes cos he didn't see that 5 in row 8
Don't fully understand the skyscrapers logic. I'll keep investigating
Maybe I get it. I will try and be able to spot the skyscrapers and empty rectangles later on.
Is the skyscraper with one slanted side named after the abominations of the architect who managed to create death rays with his design?
Which software are you using
Why at 17:12 are the 3 in the box locked in either a row or a column? What is the reasoning behind that? I hope someone explains.
At 17.00 mins why would you not enter a simple 5 in the bottom r/h 9 box.
R3C3 was penciled as being restricted to 23 only. It seems it could have been 9 as well, and therefore the empty rectangle would not have produced any result.
Never mind, I'm a dolt!
What tool are you using in these solves? It's so need with the clicking in the corresponding section of each square!
You can get it at www.littlegogs.com/
The X-wing with 4s in row 5 and 8 can be used to place a 4 in R7C2, can't it? If a 4 is ruled out of R7C3, then it can only be placed in R7C2 in that box. Can someone tell me if I'm wrong or right? I'm still new to these techniques, and would love to know if I'm understanding the X-wing technique correctly.
I found myself revisiting older CTC videos - for the benefit of others, here’s a playable version of this puzzle: sudokuexchange.com/play/?s=000607004070090010400010006600050800310000052008040003200060000060080000500204000&d=4
I got lost on 7:21 - How was it identified? What did I Miss?
You're refering the 1 or 9 central square, right? He said it in a bit of an odd way because I think he was paying the most attention to the column at the time, but you can see that it has to be 1, 6, or 9 from just the info within that 3x3 square. 6 was eliminated by looking in the 3x3 square above it.
What app/website do you use playing Sudoku
The app used in this video is Duncan's SuDoku Solver
Where's the link ? I want to try and solve it
9:00 Skyscraper & 12:40 x-wing share 2-cells. Could that matter? Seems like it.