Rules: 07:11 Let's Get Cracking: 08:10 What about this video's Top Tier Simarkisms?! The Secret: 5x (08:20, 08:23, 08:31, 08:38, 08:38) Bobbins: 1x (26:20) And how about this video's Simarkisms?! By Sudoku: 11x (21:53, 23:20, 23:54, 27:49, 28:02, 28:07, 29:46, 30:16, 35:51, 42:10, 45:25) Ah: 11x (13:20, 20:32, 21:03, 22:17, 23:05, 28:18, 29:32, 38:01, 39:27, 41:02, 43:10) Beautiful: 8x (15:30, 29:22, 33:39, 38:24, 38:26, 47:44, 48:36, 48:36) Hang On: 5x (10:47, 15:02, 17:54, 19:15, 20:09) Sorry: 4x (05:53, 17:45, 24:46, 39:43) Lovely: 4x (03:32, 03:36, 23:10, 41:36) Brilliant: 3x (02:39, 05:38, 08:07) Pencil Mark/mark: 3x (34:18, 41:13, 41:19) Hypothecate: 2x (16:55, 23:08) Good Grief: 1x (19:06) Bother: 1x (36:38) Piece of Work: 1x (03:49) Elegant: 1x (47:54) Gooseberry: 1x (46:37) Approachable: 1x (04:12) Surely: 1x (30:26) Puzzling: 1x (03:51) Obviously: 1x (03:00) Whoopsie: 1x (30:12) Progress: 1x (43:15) Plonk: 1x (42:27) Wow: 1x (39:43) Cake!: 1x (06:05) Most popular number(>9), digit and colour this video: Ten (45 mentions) Nine (94 mentions) Orange (12 mentions) Antithesis Battles: Odd (2) - Even (2) Row (5) - Column (4) FAQ: Q1: You missed something! A1: That could very well be the case! Human speech can be hard to understand for computers like me! Point out the ones that I missed and maybe I'll learn! Q2: Can you do this for another channel? A2: I've been thinking about that and wrote some code to make that possible. Let me know which channel you think would be a good fit!
When i solve Sudokus at Home (like easy ones, i‘m not THAT good) i say in my head ‚That goes there‘ and I‘M GERMAN. I literally say it in english. I watch this channel way too much 😂
Oh absolutely! As we all do. I try doing the sudokus from the apps as if i was trying to explain it to someone n i just cant do it. How Simon and Mark do this is beyond my understanding. However that said. They have a knack for explaining the logic. The only reason i can even keep up with the logic anyhow.
did this in 21:48 before watching the video, i'm proud of myself, i first identified the possible leftover digits (1, 5, 9) then proceeded to try to disqualify some of them in the boxes and just went along, pretty fun puzzle
Thanks for the 24th Wedding Anniversary shout out, Simon! My wife and I spent a lovely evening dining on home cooked food (a fabulous cottage pie) and watching Simon and Mark solve sudoku puzzles :)
I'm always impressed when I can do these puzzles without watching the video! It took me nearly two hours (1h 56m 8s to be exact), and I had a lot more pencil marks, but I'm still impressed with myself.
Numerous times I've heard you express concern that one of your videos may be too long to enjoy. Not for my taste. I can select double speed and cut the time in half if necessary. And even when I can't solve the puzzle (which is almost always true of the puzzles with "long" videos) I get hours of enjoyment from the attempt. My thanks to you, Mark and the people who create the puzzles.
There is a very interesting way to see where the left over digit can be, if you checkerboard each box you will get 5 black squares and 4 white. Each domino contains a black and white square so the left over digit can only be one of the black squares.
Omg, I'm so happy. Yesterday I tried my first, huh, complicated? sudoku, and I discarded a few I didn't even understand the rules for, but I went with this one. I couldn't do it. But today I watched the video, and a lot of my logic was right! I feel like I just got a little bit better at sudoku, thank you
Caught on to the logic needed quite quickly on this one - and looking in top left corner also really got the thing going. Total time was 18:20. Amazing puzzle!
I love Simon's doubt about whether he's missed a trick over if it's even possible to have a box that _doesn't_ have 10-dominoes, when we have had puzzles on the channel before that had four marked cages in a box that were all 9s, and four marked cages that were all 11s!
I think I was able to cut corners with this one after realizing that a) you had three classes of distribution, leaving aside either the 1, 5 or 9 with tiles adding to 11, 10 and 9 respectivelly, 2) that the left over digit could be placed only on the corners or in the center of each box to leave a set of four dominoes, while the cells orthogonal to the central one only could be part of the dominoes, and 3) when the leftover is in the corner, the central cell must be part of a domino with an adjacent cell. So, in box 1 couldn't add to 11 because the 1 was orthogonal to the center, so it was either adding to 10 with the dominoes surrounding the 5 or 9 with the leftover 9 on either top corner, and then work with the candidates in either case, leaving naked singles (the 3 and 4 in the first box) or just two candidates in each cell. This heuristic helped simplify the entire puzzle.
Ahh, this is a much better way to think about it, though its possible to solve without considering that directly. I broke into this puzzle is by considering r3c3. We know it can't be 1, 5, or 9, therefore it's in a domino attached to the either the 2 or the 1. That only gives us the possibilities of 7, 8 or 9, but 7 and 9 are already ruled out. So it's just a naked single 8 (which immediately gives the 3 in r1c2 as well). From there you can easily break into box 3, and then eventually work your way around the corners into the middle. Just considering which of the sums could be made using the few possible digits made each of the boxes a fairly simple self-contained puzzle.
I started with these same observations too! I think it was the first time I managed to solve an over-30-min-video puzzle without getting stuck somewhere halfway through... it took me about 55 mins to solve but it went rather fluidly!
@@chris5619 Simon eventually realized these things, but he realized them gradually as he observed them through the solve. But it's possible to note those things considering the domino geometry and sums abstractly from the beginning, and that makes the remaining solve a lot easier!
Yes, this is the right way to approach the puzzle. But Simon can't do this kind of analysis. Once he eventually realised that the left-over digit can't be in the middle of a side he made rather a meal of it, and also had trouble remembering this discovery later on. He is not a systematic solver.
I managed to solve this before watching, and I'm amused that I went along almost the exact same path Simon did for the first part of the video. I even chose the same colors. Guess I'm learning a lot!
I love watching these videos and sometimes participate in the sudoku myself; what I always struggle with is the initial logic to go into this. The moment Simon said each domino could only add up to 9, 10 or 11 I already thought to myself I could probably never have solved this puzzle, because I couldn't even conceive that kind of logic. These kinds of impressive deductions are what makes all you solvers stand out, and ye have my respect.
My solves so much less time would take If to my audience (which is fake) My time was not spent In a British accent Explaining each move that I make. Thanks for the inspiration, Trevor.
I finished in 59 minutes. This was such a cool and unique puzzle to solve. I found it a little difficult to scan, but I had a great time with it. I colored everything to make it easier on my brain and I found that the outlier could only exist in the corners and the center. That was neat. Also, the only possible sums were 9, 10, and 11. Even with that information, it takes a lot of work to solve this one. Great Puzzle!
An extraordinary puzzle from Aad, so elegant! I am really happy with my solve, took me 42 minutes. I first realized that only 1, 5 and 9 can be the leftovers, then that they must go into the middle or the corners which really helped. Made a little mistake in the beginning, from then on it went smoothly.
27:34 for me. I think Simon's aversion to pencil marking early on slowed him down. For example, in r3c3 for box 1, you can put an 8 at the very beginning. Because, either the box must have the leave-out number (1-5-9) or must join to 1 or 2. Well, 1 and 5 are already in the box, and 9 is in the row, so you know it joins with 1 or 2. to make 9/10/11. With a 1 or 2 you must add 7/8/9. 7/9 are ruled out by sudoku, so you know it is an 8. You can then pencil in the options for the rest of the box if it is 2-8 or 1-8. Most of the boxes let you do this.
Beautiful from all angles! One of my favourite ever deductions is r5c9 can't be 9 i found early on: In any single box 1 and 9 can never simultaneously be in breaks-tiling-if-spare positions, because then 5 is spare and tiles add up to 10 but 1 and 9 can't form a tile. Fairly simple, but signifies next tier of understanding this unique ruleset - granting me immense satisfaction.
The way dominoes tile a square with uneven cells remind me of the board game KingDomino (or follow up, slightly more advanced QueenDomino) where the players draft domino tiles to make up their kingdom in a 5 by 5 pattern with matching terrain types, and the starting castle can be somewhere in that pattern. The moment you tile a domino with the fifth cell in a row or column you lock your pattern in place and if your castle is then in the checkerboard pattern that align with the center square you can (possibly, if a little lucky with draft, draw and terrain types) tile the entire square, and if the castle ended up on the off-square you are doomed to discard at least one domino and miss out on potential points. A really simple and cool game, easy to introduce to kids from as low as 6-7 years and still provide adequate challenge for their parents! Also a great puzzle from Aard and great solve from Simon!
42:47 - "I keep messing up my modes" Some trivia: That is called a "mode error" which is a prevalent issue in software development and engineering which has led to plane crashes among other things. (Sven's software is actually quite accommodating as it can be used in a modeless way as well - for the most part - by staying in digit mode using modifier keys for pencil marks, candidates and colors.)
I have now learned to click the like button *_before_* I watch the video. You get so caught up while watching that you sometimes forget. That's not fair on you guys!
Well, that took several attempts and quite a lot of Saturday, but I did finally manage to solve it by myself, having worked out the possible domino totals and the possible locations of the spare digit, and I can't often say that about a puzzle with a 49-minute video, so I'm feeling pleased with myself!
A very pretty rule set. It's quite easy to do the break-ins via the checkerboard invariant: if you color the 3x3 box like a checkerboard you will have five cells of one color (corners+center) and four of the other color, and as each domino covers one black and one white cell, the leftover cell will always be one of the five.
Took me 80 mins but did it on my own. Got the 1,5,9/11,10,9 relationship straight away. Realised the checkerboard 80% through and it became fairly easy after that.
I feel like Simon missed something very cool about the logic, which is that in most of the boxes, the positions of some digits are the same regardless of the eventual sum. In box 1, for instance, you can rule out 11 immediately, but then if you look at the possible positions for both 9 and 10 dominoes, you can determine that the positions of 3, 4, 8, and 9 are the same regardless of whether the dominoes sum to 9 or 10. And that pattern continues around the puzzle. This was such a lovely puzzle, I really enjoyed it!
The moment when Simon missed the 9 2 logic in box 4, which was the same as he started the puzzle with, then immediately used the same logic in box 8. Made me chuckle a little. Love you Simon
I was astonished at how easy this puzzle was. I took it nice and slow, of course. It took me a little while to recognize that my usual starting practice of corner-marking digits in blocks would be useless. Filling out the six-digit rows and columns was considerably more useful. The domino sums (consequently, the spare digits) were severely restricted. The location in blocks of the spare digit was less restricted. Once I filled in digits (or pairs) I colored them, a different color for each domino pair. (Fortunately, I only needed eight colors, and not twelve.) This was useful with my memory issues -- I could identify the dominoes and see and recall what they summed to. 10:30 It helped that I first center-marked the digits in the rows and columns with six given digits. But after that, I did work around the grid with each block -- corner blocks first, of course. 11:20 In each block, I filled each cell with all possible candidates, then gradually ruled them out. (I don't usually this early in Sudoku.) 15:30 The spare cells are restricted to the centers and corners of the blocks. 23:00 Filling out the rows and columns will help. It seems as if Simon's making the puzzle harder for him than it was for me. 23:40 "We don't want to debase ourselves too early in doing Sudoku in Sudoku puzzles." Speak for yourself. As a mediocre Sudoku puzzler, I need every tool I can get. 32:00 No, two boxes are nine-sum. None are eleven-sum. 48:20 Yes, that restriction on the spare cells was critical. The END: Thanks for the video. And thanks for a puzzle that I found surprisingly approachable.
Loved the music, the setting, and the solving!! Such an original idea for a puzzle, I love the tiling trick with the problem of isolating a digit on the middle of a side! PS: two dominoes were left unconnected, and you never clicked check!
44:31 for me - It took a few minutes to do the math and figure out that the odd number out must be 1, 5 or 9. 30 minutes in and I realize that the odd digit must be in the middle or on a corner.
Wow for the first time ever I was able to solve a puzzle quicker than you, usually I don't solve thaem at all haha! There is a very easy way to solve the first digit. So in the top left 3x3 sq. We know that the domino is either 9 or 10. If it were to be a 9 there has to be a 4 at the 5's left, but if that were the case there had to be a 7 next to the 2 and a 9 at the bottom also. That is impossible so the domino sum is 10. From that we can easily deduce that there is a 9 above the 1, and the 3x3 is pretty much solved in half a minute. Keep up the great work!
Absolutely loved this puzzle. Realised very quickly that placing the remainder was crucial to tiling the boxes and headed on from there. Great work Aad, thank you so much!
I rarely tackle (and even more rarely solve) the puzzles, but I was really happy that I remembered the secret when I did and used that to my advantage. 50 minute solve time made me feel really good about it!
i can't believe i manage to solve this puzzle on my own and i notice a lot of unique things to solve this puzzle. still it took way to long for me to solve but in the end i'm glad i can solve it (79min). nice puzzle aad
34:11, I figured out that the digits not in pairs had to be 1, 5, or 9 only and that certain cells HAD to be in pairs or they would break the 3x3 box pretty quickly. It was fun after that, though a bunch of trial and error. And I had a stupid mistake in Box 7 at the end.
It's not just the math that's amazing, but also the memory required to even be able to do the math. (the immediate memory to retain each symptom and then use those symptoms to diagnose and cure... because I can't think of the right words). For me that's the hard part. I have no doubt that these kinds of puzzles will improve your memory, especially short term memory).
Weird. I figured out the tiling almost immediately, but still took almost two hours because some logic was off. Probably assumed all extras were fives, so required backtracking. Is helping with my logical think. Fun.
One way to think about the tiling is to colour it like a chess board with black in the middle so that you have 5 black squares and 4 white. Then understand that each domino uses 1 white squares and one black. Then your see that the left over square is always black. Maybe not a tool needed for 3x3s but a handy tool for thinking about larger puzzles.
An early digit can be placed in box 1. The bottom right can't be the spare digit because sudoku eliminates 1 5 or 9. So it must be part of a domino pairing with 1 or 2. And the domino must sum to 9, 10 or 11. So the bottom right cell must be 7, 8 or 9 and by sudoku it's 8.
Got this one in 37:33. Once I realized the only 3 options for the leftover digits, it wasn't too hard to figure out the corners, then the middles, then the center.
If you think of the box as a 3 x 3 grid, and consider adding the coordinates of each cell, every domino takes one cell with even coordinate sum and one with odd. So the leftover cell has to have even coordinate sum, since there are 5 of those and 4 of the other. This is why the middle cells in the outer rows/columns cannot be the leftover cell.
Really nice puzzle, it took me 61 minutes. Now, I am a very beginner in sudoku that have a different set of rules from the usual, so my time is quite long. But I found this puzzle very interesting and pretty approachable for a beginner!
I didn't know the secret, but came up with the fact the unpaired digit in each box must be 1, 5 or 9, with a corresponding sum of 11, 10 or 9. It's the only way you can get symmetrical groups of four high digits and four low digits that all sum to the same number. If the unpaired number was a 2, you'd get 1 + 9 = 10, then skip over 2 for 8 + 3 = 11, and everything else would sum to 11 as well. If the group of four low numbers or high numbers is split by the unpaired number, you get this problem.
I think you'd have got off to a better start if you'd pencil-marked the missing three digits in the occupied rows & columns. In box 1, both possible options resulted in several cells having the same value, e.g. R3C3 was always 8, and R1C2=3. This placed restrictions on other boxes, which cut down their alternatives and made them easier to resolve. Apart from box 1, I was always able to restrict each box I considered to just one sum, which made the solution path very smooth. A very enjoyable and quite different puzzle. Aad always manages to come up with interesting puzzles that make you think in slightly different ways.
I usually judge how difficult these puzzles are by the length of the video. Around 30mins? I might be able to do it in 90. Usually when they are pushing the hour mark I know they are beyond me. However, I tried this one and found it pretty simple. There wasn’t even much sudoku. Still took my around 50 minutes which is actually good for me.
Funny how minds differ - I started by working out that the only totals that can be made 4 ways are 9, 10 and 11. I also pencil marked the spaces in the given rows and columns which helped narrow down the possible dominoes.
I missed the generic observation that the non-domino digit can't be at the middle of a side of a box, which made the whole puzzle a lot more difficult. (I guess I found it in some specific cases near the end, e.g. in box 6.) I added all the partial domino-borders between the tiles as I found them (i.e. in box 1, starting between 5|1 and 5|1), which later helped me to see where potential dominos would be. Then I used differently-colored connecting lines for the different potential sums in a box. (145:06, spread over two days.)
Someone might find this funny. I tried solving the puzzle three times and I got stuck in the same place each time. All of my logic was correct, I was certain. I finally compared my partial solution to Simon's, and it turns out my very first deduction was wrong. I had double clicked the sevens and said "four sevens looking at the middle box", and put a 7 in the middle.
I also used coloring for the sums by box and the line tool to track the dominoes with more marking of edges that couldn't join. But my solve path felt different, less cyclical than yours - for the most part just going from one box to the next and solving all but a pair. Because of that, the puzzle became less interesting over the course of solve after the initial break-in.
64:13 for me, but I got distracted by phone and didn't pause the puzzle. I came really far until box 7 where I made a slip and filled in wrongly. I watched your video at this position and noticed my errors. :D I've done a LOT of GAS in the last weeks and now I feel comfortable doing bigger puzzles and this was a good entrance but I need to be a bit more careful here with too fast deductions. (leading to errors)
That's a mutilated chessboard theorem. If you color the tiles in a chessboard pattern, then you can only fill a shape with dominoes if there's 4 of one and 4 of the other colour (4 in this case, equal in general) Therefore the "leftover" cell can only be a corner cell or a middle cell, not an edge cell.
27:07 for me. This is the first time I’ve solved one faster than Simon I think. Though I might have cheated because I never considered 11 to be a possible sum in a domino.
There is a famous puzzle: Given a chess board where two fields are missing: a1 and h8 (opposite corners). Can we cover the remaining 62 fields with 31 dominoes? spoiler alert... The solution is remarkable simple: since each domino covers a white and a black square, and we have 30 fields of one color and 32 of the other, we'll never be able to cover them all. Knowing this puzzle helped me a lot, at the start: I could colour in all cells at the middle of each box edge as well as each cell containing a 2,3,4,678, because they had to be in a domino.
I could _maybe_ solve these puzzles faster if I didn’t explain every deduction I make to an imaginary audience with a fake British accent
I find it a great exercize to be sure
It's not just me?
I thought I was the only nut in this nuthouse! Thank you for making me feel better about talking to myself. 😂🎉
This is my nomination for 2022 Comment of the Year
Yeah another one here 😆
I love it when you tell us the secret. I heard it loads of times but each time feels special 😂
Shhh, don't tell anyone.
I actually got to use the secret doing my first sandwich sudoku yesterday
Rules: 07:11
Let's Get Cracking: 08:10
What about this video's Top Tier Simarkisms?!
The Secret: 5x (08:20, 08:23, 08:31, 08:38, 08:38)
Bobbins: 1x (26:20)
And how about this video's Simarkisms?!
By Sudoku: 11x (21:53, 23:20, 23:54, 27:49, 28:02, 28:07, 29:46, 30:16, 35:51, 42:10, 45:25)
Ah: 11x (13:20, 20:32, 21:03, 22:17, 23:05, 28:18, 29:32, 38:01, 39:27, 41:02, 43:10)
Beautiful: 8x (15:30, 29:22, 33:39, 38:24, 38:26, 47:44, 48:36, 48:36)
Hang On: 5x (10:47, 15:02, 17:54, 19:15, 20:09)
Sorry: 4x (05:53, 17:45, 24:46, 39:43)
Lovely: 4x (03:32, 03:36, 23:10, 41:36)
Brilliant: 3x (02:39, 05:38, 08:07)
Pencil Mark/mark: 3x (34:18, 41:13, 41:19)
Hypothecate: 2x (16:55, 23:08)
Good Grief: 1x (19:06)
Bother: 1x (36:38)
Piece of Work: 1x (03:49)
Elegant: 1x (47:54)
Gooseberry: 1x (46:37)
Approachable: 1x (04:12)
Surely: 1x (30:26)
Puzzling: 1x (03:51)
Obviously: 1x (03:00)
Whoopsie: 1x (30:12)
Progress: 1x (43:15)
Plonk: 1x (42:27)
Wow: 1x (39:43)
Cake!: 1x (06:05)
Most popular number(>9), digit and colour this video:
Ten (45 mentions)
Nine (94 mentions)
Orange (12 mentions)
Antithesis Battles:
Odd (2) - Even (2)
Row (5) - Column (4)
FAQ:
Q1: You missed something!
A1: That could very well be the case! Human speech can be hard to understand for computers like me! Point out the ones that I missed and maybe I'll learn!
Q2: Can you do this for another channel?
A2: I've been thinking about that and wrote some code to make that possible. Let me know which channel you think would be a good fit!
whoa! bot, you are super fast!
Thanks bot. Not everyone wants to know that Niblock and BreezyTrousers have a birthday.
@@malcolmjohnson4414 its still cute tho
You playing So Far Away made me tear up! You are a talented guitar player as you are an amazing puzzle solver and a lovely entertainer! Love you Simon
When i solve Sudokus at Home (like easy ones, i‘m not THAT good) i say in my head ‚That goes there‘ and I‘M GERMAN. I literally say it in english.
I watch this channel way too much 😂
I'm doing that too! Also German here :D
Oh absolutely! As we all do. I try doing the sudokus from the apps as if i was trying to explain it to someone n i just cant do it. How Simon and Mark do this is beyond my understanding. However that said. They have a knack for explaining the logic. The only reason i can even keep up with the logic anyhow.
Same! I'm Italian and I find myself thinking in English!
Donner und bobbins!
It's totally the same with me, german in normal life, Simon-english in Sudoku. And I can't fight it!
did this in 21:48 before watching the video, i'm proud of myself, i first identified the possible leftover digits (1, 5, 9) then proceeded to try to disqualify some of them in the boxes and just went along, pretty fun puzzle
Thanks for the 24th Wedding Anniversary shout out, Simon! My wife and I spent a lovely evening dining on home cooked food (a fabulous cottage pie) and watching Simon and Mark solve sudoku puzzles :)
I officially did one faster than Simon! This is a Great Day! I must call my mom, my family, and my friends! Woot!
One of the best songs ever written. Extremely emotional video, esp the end with the home movies and photos.
RIP Rev!
I'm always impressed when I can do these puzzles without watching the video! It took me nearly two hours (1h 56m 8s to be exact), and I had a lot more pencil marks, but I'm still impressed with myself.
From "AJ's Dad" - thanks for the shout out on my birthday! Updated the stats from Inspiring Sand too! Had lots of cake, thanks Simon!
Really nice surprise in the intro! I love Avenged Sevenfold and So Far Away used to be my favorite song when I first heard it!
Numerous times I've heard you express concern that one of your videos may be too long to enjoy. Not for my taste. I can select double speed and cut the time in half if necessary. And even when I can't solve the puzzle (which is almost always true of the puzzles with "long" videos) I get hours of enjoyment from the attempt. My thanks to you, Mark and the people who create the puzzles.
Simon: And that's impossible, because what I'm left with in these two cells is...
Me: A _FACE!_
Simon: ...not a domino
Me: Mmm yes of course
Well a face is not a domino!
There is a very interesting way to see where the left over digit can be, if you checkerboard each box you will get 5 black squares and 4 white. Each domino contains a black and white square so the left over digit can only be one of the black squares.
I now want a proof.
So corner or middle
@@fornife5004 the white ones will be on the "middle of the sides" of the boxes, like the 1s, 5s and 9s Simon looked for
... or 5 white squares and 4 blacks! 😉
@@fornife5004 What I wrote is a proof that the left over digit can only be in the middle or the corners :)
Omg, I'm so happy. Yesterday I tried my first, huh, complicated? sudoku, and I discarded a few I didn't even understand the rules for, but I went with this one. I couldn't do it. But today I watched the video, and a lot of my logic was right! I feel like I just got a little bit better at sudoku, thank you
Caught on to the logic needed quite quickly on this one - and looking in top left corner also really got the thing going. Total time was 18:20. Amazing puzzle!
6:25 “Harrieb Al Sack”😂😂😂
I love Simon's doubt about whether he's missed a trick over if it's even possible to have a box that _doesn't_ have 10-dominoes, when we have had puzzles on the channel before that had four marked cages in a box that were all 9s, and four marked cages that were all 11s!
I think I was able to cut corners with this one after realizing that a) you had three classes of distribution, leaving aside either the 1, 5 or 9 with tiles adding to 11, 10 and 9 respectivelly, 2) that the left over digit could be placed only on the corners or in the center of each box to leave a set of four dominoes, while the cells orthogonal to the central one only could be part of the dominoes, and 3) when the leftover is in the corner, the central cell must be part of a domino with an adjacent cell.
So, in box 1 couldn't add to 11 because the 1 was orthogonal to the center, so it was either adding to 10 with the dominoes surrounding the 5 or 9 with the leftover 9 on either top corner, and then work with the candidates in either case, leaving naked singles (the 3 and 4 in the first box) or just two candidates in each cell. This heuristic helped simplify the entire puzzle.
It helped Simon as well.
Ahh, this is a much better way to think about it, though its possible to solve without considering that directly.
I broke into this puzzle is by considering r3c3. We know it can't be 1, 5, or 9, therefore it's in a domino attached to the either the 2 or the 1. That only gives us the possibilities of 7, 8 or 9, but 7 and 9 are already ruled out. So it's just a naked single 8 (which immediately gives the 3 in r1c2 as well). From there you can easily break into box 3, and then eventually work your way around the corners into the middle. Just considering which of the sums could be made using the few possible digits made each of the boxes a fairly simple self-contained puzzle.
I started with these same observations too! I think it was the first time I managed to solve an over-30-min-video puzzle without getting stuck somewhere halfway through... it took me about 55 mins to solve but it went rather fluidly!
@@chris5619 Simon eventually realized these things, but he realized them gradually as he observed them through the solve. But it's possible to note those things considering the domino geometry and sums abstractly from the beginning, and that makes the remaining solve a lot easier!
Yes, this is the right way to approach the puzzle. But Simon can't do this kind of analysis. Once he eventually realised that the left-over digit can't be in the middle of a side he made rather a meal of it, and also had trouble remembering this discovery later on. He is not a systematic solver.
I managed to solve this before watching, and I'm amused that I went along almost the exact same path Simon did for the first part of the video. I even chose the same colors. Guess I'm learning a lot!
Wow, really wasn't expecting to win the drawing, shocked me at midnight when I watched this! Really honoured, the game sounds so fun!
I love watching these videos and sometimes participate in the sudoku myself; what I always struggle with is the initial logic to go into this. The moment Simon said each domino could only add up to 9, 10 or 11 I already thought to myself I could probably never have solved this puzzle, because I couldn't even conceive that kind of logic.
These kinds of impressive deductions are what makes all you solvers stand out, and ye have my respect.
I must say when I clicked on this video I did not expect Avenged Sevenfold and I absolutely love it! Simon can't stop being awesome.
My solves so much less time would take
If to my audience (which is fake)
My time was not spent
In a British accent
Explaining each move that I make.
Thanks for the inspiration, Trevor.
I finished in 59 minutes. This was such a cool and unique puzzle to solve. I found it a little difficult to scan, but I had a great time with it. I colored everything to make it easier on my brain and I found that the outlier could only exist in the corners and the center. That was neat. Also, the only possible sums were 9, 10, and 11. Even with that information, it takes a lot of work to solve this one. Great Puzzle!
What a fun and approachable puzzle. The first time I've been able to solve a puzzle without help from the video!!
What a beautiful rendition of So Far Away in the intro!
An extraordinary puzzle from Aad, so elegant! I am really happy with my solve, took me 42 minutes. I first realized that only 1, 5 and 9 can be the leftovers, then that they must go into the middle or the corners which really helped. Made a little mistake in the beginning, from then on it went smoothly.
I can't believe it...I actually solved this one!! 😲
It took the first hints from Simon and a buttload of time, but I did it!
27:34 for me. I think Simon's aversion to pencil marking early on slowed him down. For example, in r3c3 for box 1, you can put an 8 at the very beginning. Because, either the box must have the leave-out number (1-5-9) or must join to 1 or 2. Well, 1 and 5 are already in the box, and 9 is in the row, so you know it joins with 1 or 2. to make 9/10/11. With a 1 or 2 you must add 7/8/9. 7/9 are ruled out by sudoku, so you know it is an 8. You can then pencil in the options for the rest of the box if it is 2-8 or 1-8. Most of the boxes let you do this.
8 is a powerful number with this rule set, I used the fact it has so few possible friends to make quite a lot of progress.
Thank Aad van de Wetering and Simon. It was a nice and a special puzzle!
Beautiful from all angles! One of my favourite ever deductions is r5c9 can't be 9 i found early on:
In any single box 1 and 9 can never simultaneously be in breaks-tiling-if-spare positions, because then 5 is spare and tiles add up to 10 but 1 and 9 can't form a tile. Fairly simple, but signifies next tier of understanding this unique ruleset - granting me immense satisfaction.
29:22 finish. A very interesting concept. Excellent!
The way dominoes tile a square with uneven cells remind me of the board game KingDomino (or follow up, slightly more advanced QueenDomino) where the players draft domino tiles to make up their kingdom in a 5 by 5 pattern with matching terrain types, and the starting castle can be somewhere in that pattern. The moment you tile a domino with the fifth cell in a row or column you lock your pattern in place and if your castle is then in the checkerboard pattern that align with the center square you can (possibly, if a little lucky with draft, draw and terrain types) tile the entire square, and if the castle ended up on the off-square you are doomed to discard at least one domino and miss out on potential points. A really simple and cool game, easy to introduce to kids from as low as 6-7 years and still provide adequate challenge for their parents!
Also a great puzzle from Aard and great solve from Simon!
42:47 - "I keep messing up my modes"
Some trivia: That is called a "mode error" which is a prevalent issue in software development and engineering which has led to plane crashes among other things.
(Sven's software is actually quite accommodating as it can be used in a modeless way as well - for the most part - by staying in digit mode using modifier keys for pencil marks, candidates and colors.)
I have now learned to click the like button *_before_* I watch the video. You get so caught up while watching that you sometimes forget. That's not fair on you guys!
Well, that took several attempts and quite a lot of Saturday, but I did finally manage to solve it by myself, having worked out the possible domino totals and the possible locations of the spare digit, and I can't often say that about a puzzle with a 49-minute video, so I'm feeling pleased with myself!
A very pretty rule set. It's quite easy to do the break-ins via the checkerboard invariant: if you color the 3x3 box like a checkerboard you will have five cells of one color (corners+center) and four of the other color, and as each domino covers one black and one white cell, the leftover cell will always be one of the five.
48:50 for me. God bless Sven's software, the pen tool came especially in handy for this one
Did anyone else notice Simon draw a screaming totemic head in the top right at 15:20? Just me? Cool Cool!
Took me 80 mins but did it on my own. Got the 1,5,9/11,10,9 relationship straight away. Realised the checkerboard 80% through and it became fairly easy after that.
I feel like Simon missed something very cool about the logic, which is that in most of the boxes, the positions of some digits are the same regardless of the eventual sum. In box 1, for instance, you can rule out 11 immediately, but then if you look at the possible positions for both 9 and 10 dominoes, you can determine that the positions of 3, 4, 8, and 9 are the same regardless of whether the dominoes sum to 9 or 10. And that pattern continues around the puzzle. This was such a lovely puzzle, I really enjoyed it!
The moment when Simon missed the 9 2 logic in box 4, which was the same as he started the puzzle with, then immediately used the same logic in box 8. Made me chuckle a little. Love you Simon
I was astonished at how easy this puzzle was. I took it nice and slow, of course. It took me a little while to recognize that my usual starting practice of corner-marking digits in blocks would be useless. Filling out the six-digit rows and columns was considerably more useful. The domino sums (consequently, the spare digits) were severely restricted. The location in blocks of the spare digit was less restricted. Once I filled in digits (or pairs) I colored them, a different color for each domino pair. (Fortunately, I only needed eight colors, and not twelve.) This was useful with my memory issues -- I could identify the dominoes and see and recall what they summed to.
10:30 It helped that I first center-marked the digits in the rows and columns with six given digits. But after that, I did work around the grid with each block -- corner blocks first, of course.
11:20 In each block, I filled each cell with all possible candidates, then gradually ruled them out. (I don't usually this early in Sudoku.)
15:30 The spare cells are restricted to the centers and corners of the blocks.
23:00 Filling out the rows and columns will help. It seems as if Simon's making the puzzle harder for him than it was for me.
23:40 "We don't want to debase ourselves too early in doing Sudoku in Sudoku puzzles." Speak for yourself. As a mediocre Sudoku puzzler, I need every tool I can get.
32:00 No, two boxes are nine-sum. None are eleven-sum.
48:20 Yes, that restriction on the spare cells was critical.
The END: Thanks for the video. And thanks for a puzzle that I found surprisingly approachable.
Loved the music, the setting, and the solving!! Such an original idea for a puzzle, I love the tiling trick with the problem of isolating a digit on the middle of a side! PS: two dominoes were left unconnected, and you never clicked check!
18:57 for me, loved this puzzle and the logic behind it! Definitely one of my favorites from the channel
44:31 for me - It took a few minutes to do the math and figure out that the odd number out must be 1, 5 or 9. 30 minutes in and I realize that the odd digit must be in the middle or on a corner.
Wow for the first time ever I was able to solve a puzzle quicker than you, usually I don't solve thaem at all haha! There is a very easy way to solve the first digit. So in the top left 3x3 sq. We know that the domino is either 9 or 10. If it were to be a 9 there has to be a 4 at the 5's left, but if that were the case there had to be a 7 next to the 2 and a 9 at the bottom also. That is impossible so the domino sum is 10. From that we can easily deduce that there is a 9 above the 1, and the 3x3 is pretty much solved in half a minute. Keep up the great work!
Great song choice, seen them at download and i cried when they played this. R.I.P. Rev
Absolutely loved this puzzle. Realised very quickly that placing the remainder was crucial to tiling the boxes and headed on from there. Great work Aad, thank you so much!
Omg he played So Far Away. I need more of that in my life.
43:12 ... another gem from Aad
Wonderful puzzle!
I rarely tackle (and even more rarely solve) the puzzles, but I was really happy that I remembered the secret when I did and used that to my advantage. 50 minute solve time made me feel really good about it!
15:55 for me. What an interesting puzzle!! Loved the ruleset!
i can't believe i manage to solve this puzzle on my own and i notice a lot of unique things to solve this puzzle. still it took way to long for me to solve but in the end i'm glad i can solve it (79min). nice puzzle aad
34:11, I figured out that the digits not in pairs had to be 1, 5, or 9 only and that certain cells HAD to be in pairs or they would break the 3x3 box pretty quickly. It was fun after that, though a bunch of trial and error. And I had a stupid mistake in Box 7 at the end.
I had an error in box 7 as well.
What a neat idea for a puzzle. Yet again Aad is setting tremendous puzzles and Simon is solving them! Kudos
36:07 for me, which is, by my standards, very quick, so I'm more than happy with that result!
Just under an hour for me. Very different but most enjoyable.
It's not just the math that's amazing, but also the memory required to even be able to do the math. (the immediate memory to retain each symptom and then use those symptoms to diagnose and cure... because I can't think of the right words). For me that's the hard part. I have no doubt that these kinds of puzzles will improve your memory, especially short term memory).
Brilliant puzzle! 39:20 here.
Weird. I figured out the tiling almost immediately, but still took almost two hours because some logic was off. Probably assumed all extras were fives, so required backtracking. Is helping with my logical think. Fun.
So cool. Thank you for sharing.
One way to think about the tiling is to colour it like a chess board with black in the middle so that you have 5 black squares and 4 white. Then understand that each domino uses 1 white squares and one black. Then your see that the left over square is always black. Maybe not a tool needed for 3x3s but a handy tool for thinking about larger puzzles.
An early digit can be placed in box 1. The bottom right can't be the spare digit because sudoku eliminates 1 5 or 9. So it must be part of a domino pairing with 1 or 2. And the domino must sum to 9, 10 or 11. So the bottom right cell must be 7, 8 or 9 and by sudoku it's 8.
Got this one in 37:33. Once I realized the only 3 options for the leftover digits, it wasn't too hard to figure out the corners, then the middles, then the center.
Never thought I'd hear a song from my favourite band in the intro of a CtC video. You guys just keep amazing me😍
Oooh, you use colors to mark the possible sums. Of course!
If you think of the box as a 3 x 3 grid, and consider adding the coordinates of each cell, every domino takes one cell with even coordinate sum and one with odd. So the leftover cell has to have even coordinate sum, since there are 5 of those and 4 of the other. This is why the middle cells in the outer rows/columns cannot be the leftover cell.
45:50 "I havn't got [any] 11-boxes, I've just got 9-boxes [...]" yes, Sudoku is all about filling the 9 boxes! xD
Really nice puzzle, it took me 61 minutes. Now, I am a very beginner in sudoku that have a different set of rules from the usual, so my time is quite long. But I found this puzzle very interesting and pretty approachable for a beginner!
Yay, finished this in 38 minutes without looking at the video once! I wonder if we followed the same path
I didn't know the secret, but came up with the fact the unpaired digit in each box must be 1, 5 or 9, with a corresponding sum of 11, 10 or 9.
It's the only way you can get symmetrical groups of four high digits and four low digits that all sum to the same number.
If the unpaired number was a 2, you'd get 1 + 9 = 10, then skip over 2 for 8 + 3 = 11, and everything else would sum to 11 as well. If the group of four low numbers or high numbers is split by the unpaired number, you get this problem.
I think you'd have got off to a better start if you'd pencil-marked the missing three digits in the occupied rows & columns. In box 1, both possible options resulted in several cells having the same value, e.g. R3C3 was always 8, and R1C2=3. This placed restrictions on other boxes, which cut down their alternatives and made them easier to resolve. Apart from box 1, I was always able to restrict each box I considered to just one sum, which made the solution path very smooth.
A very enjoyable and quite different puzzle. Aad always manages to come up with interesting puzzles that make you think in slightly different ways.
I usually judge how difficult these puzzles are by the length of the video. Around 30mins? I might be able to do it in 90. Usually when they are pushing the hour mark I know they are beyond me. However, I tried this one and found it pretty simple. There wasn’t even much sudoku. Still took my around 50 minutes which is actually good for me.
Solved myself finally without hints by watching Simon. We won’t discuss times tho.
Great puzzle! Love the rules 😃
Funny how minds differ - I started by working out that the only totals that can be made 4 ways are 9, 10 and 11. I also pencil marked the spaces in the given rows and columns which helped narrow down the possible dominoes.
~45mins. pretty cool puzzle, sounds so simple but it's really cool :) ❤❤❤❤❤❤
One of the best intro so far
48 min, not too bad for me--thanks as always Aad and Simon
I missed the generic observation that the non-domino digit can't be at the middle of a side of a box, which made the whole puzzle a lot more difficult. (I guess I found it in some specific cases near the end, e.g. in box 6.) I added all the partial domino-borders between the tiles as I found them (i.e. in box 1, starting between 5|1 and 5|1), which later helped me to see where potential dominos would be. Then I used differently-colored connecting lines for the different potential sums in a box.
(145:06, spread over two days.)
38:47, actually proud of myself on this one
I thought about the same example in 3rd box… (when you read the rules about dominoes)
insane!
Beautiful A7X intro!!
Great puzzle, approachable and interesting.
90 minutes, pretty cool puzzle.
Someone might find this funny. I tried solving the puzzle three times and I got stuck in the same place each time. All of my logic was correct, I was certain. I finally compared my partial solution to Simon's, and it turns out my very first deduction was wrong.
I had double clicked the sevens and said "four sevens looking at the middle box", and put a 7 in the middle.
I also used coloring for the sums by box and the line tool to track the dominoes with more marking of edges that couldn't join. But my solve path felt different, less cyclical than yours - for the most part just going from one box to the next and solving all but a pair. Because of that, the puzzle became less interesting over the course of solve after the initial break-in.
64:13 for me, but I got distracted by phone and didn't pause the puzzle. I came really far until box 7 where I made a slip and filled in wrongly. I watched your video at this position and noticed my errors. :D I've done a LOT of GAS in the last weeks and now I feel comfortable doing bigger puzzles and this was a good entrance but I need to be a bit more careful here with too fast deductions. (leading to errors)
Was Simon throwing some major shade at Mark? 🌲
This one felt like pulling teeth to me! Very difficult. Felt like doing 9 back to back puzzles the way I did it. Then again, it took me 89 minutes!
36:15 for me. Went a little bifurcate-y in my solve, but still fairly proud.
32:43 very fun puzzle
38:29 for me, which is good by my own averages, but my happiness is marred by the fact that Simon left two 6-4 dominoes unmarked at the end.
Cute and delightful puzzle :D
That's a mutilated chessboard theorem. If you color the tiles in a chessboard pattern, then you can only fill a shape with dominoes if there's 4 of one and 4 of the other colour (4 in this case, equal in general)
Therefore the "leftover" cell can only be a corner cell or a middle cell, not an edge cell.
27:07 for me. This is the first time I’ve solved one faster than Simon I think. Though I might have cheated because I never considered 11 to be a possible sum in a domino.
There is a famous puzzle: Given a chess board where two fields are missing: a1 and h8 (opposite corners). Can we cover the remaining 62 fields with 31 dominoes?
spoiler alert...
The solution is remarkable simple: since each domino covers a white and a black square, and we have 30 fields of one color and 32 of the other, we'll never be able to cover them all.
Knowing this puzzle helped me a lot, at the start: I could colour in all cells at the middle of each box edge as well as each cell containing a 2,3,4,678, because they had to be in a domino.
Very pretty and enjoyable puzzle.