Expert Sudoku: Overlapping Wings

Expert Sudoku: Overlapping Wings - What Are They?!

Рет қаралды 19,336

4 жыл бұрын

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Hi! We're Simon Anthony and Mark Goodliffe, two of the UK's most enthusiastic puzzle solvers. We have both represented the UK at the World Sudoku Championships and the World Puzzle Championships. We're also "cryptic crossword" aficionados. Mark is the eleven-time winner of The Times championship and Simon is the former record holder for most consecutive correct solutions to The Listener crossword. We hope we can help your puzzle solving while also introducing you to some of the world's best puzzles.
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Пікірлер: 63

@stefanwaal 4 жыл бұрын

@10:00 When I solved it I noticed something over here. R4C2 can only be a 2, 3, or 7. If it is either a 2 or a 7 there's a 2-7 pair in C2. Combine this with the 2 and the 7 in box 8 and we can conclude R9C1 has to be both a 2 and a 7. That's impossible, so R4C2 has to be a 3.

@04LightningFan 4 жыл бұрын

Very clever.

@Qazqi 4 жыл бұрын

9:38 r8c1 is 136, which can bring in uniqueness on r8c13 and r3c13 to make r8c1 a 1. If you do this, the puzzle collapses without even an X-wing, which I found interesting.

@megaminxpll 4 жыл бұрын

Yeah, I solved it like that also.

@tallrapp 4 жыл бұрын

How'd you get 13 columns? I only have 9.

@Qazqi 4 жыл бұрын

@@tallrapp It's shorthand for columns 1 and 3.

@rabidsamfan 4 жыл бұрын

I used the same constraint, eliminating 3 and 6 from r8c1 in my head from the parallel pair in row 3, and with 8 already in the box 1 was all that remained.

@goldenera7090 4 жыл бұрын

yes I did the same way but I found it 2 min later than you. well done.

@lucasmandato4910 4 жыл бұрын

i found it wonderfull the way you continued with the "hard logic" after the 7 you found in the doble formation, i was stuck exactly at the same place, and with the 7 it collapsed...and that was gorgeous to see you doing in a more "IQ expending" way ...

@blobdffoo819 3 жыл бұрын

Wow this was an amazing puzzle, i think i figured the right thing about overlapping wings on 36, but this was the first part because i had to find out how to use it ! No bifurcating used feels so nice

@Pyromonkey83 4 жыл бұрын

Relatively easy 12 minute solve for me. I did use uniqueness, however, which is a technique many consider against the "spirit" of a puzzle, but in a speed solving situation, its always a relevant option. Well designed puzzle though, constantly giving you small bits of necessary information with a solid variety of hidden techniques. Good fun all around.

@12tone 4 жыл бұрын

Didn't time myself but I don't think it took me _too_ long. No bifurcating but I did use uniqueness at one point, and then when I got a bit stuck I started hunting for swordfish-style logic and wound up finding a jellyfish on 6s that broke it wide open.

@wescraven2606 4 жыл бұрын

This was a really great video. Thanks for showing the swordfish.

@eireannsg 4 жыл бұрын

20:55 at a certain point you want to start cleaning up the mess but you dont pay attention to the most obvious-...1 in c1r8 and 1,8 in c7r8. instead you keep concentrating on finding the more difficult.

@not2tees 4 жыл бұрын

Brutal! I watch, hope to learn . . . yes.

@BloodyxScy 4 жыл бұрын

This was the first puzzle I've tried, since it looked doable for me, took me 14:45, I'm proud!

@bristolrovers27 4 жыл бұрын

Another great solve

@jimdetry9420 4 жыл бұрын

My solve was almost identical to yours except I used the X wing on 6s and the uniqueness on 36 pairs, then didn't need the y wing.

@richardj3880 4 жыл бұрын

That was a bit tough for me but found the uniqueness on 36's (R3,R7) to exclude 36 from R7C1 so it had to be a 1 and plodded troug te rest OK. Nice video - I must admit I regularly don't manage to solve the puzzles, but I do like to try.

@slb050568 3 жыл бұрын

One thing i can say that I do that helps is to finish the logic w each single number. In the begining he missed an 85 pair that would have givin him a 1 and 4 bc he didn't finish marking the 5s which would have shown him the 85

@slb050568 3 жыл бұрын

and a 36 pair which would have given him a 2 and 9..

@RO8s 3 жыл бұрын

Well, I'm encouraged by the fact that I reached exactly the same place he did when I hit the wall. I need to break through to the next level. It's close, I can feel it...

@04LightningFan 4 жыл бұрын

Hey Simon, from watching your video, I'm getting better at spotting X-wings. So, thank you for that. When I was at a point similar to you at 7:12, my eyes were drawn to the 36 pairs in rows 2 & 3. It looked like 4 opportunities to find an X-wing. Looking down I noticed that row 8 had empty cells in the same columns, 1, 3, 7, & 9. Then I noticed that because of the 3 and 6 in column 4, row 6 had a similar pattern. I didn't know it was called a jellyfish, but I did notice that we had two candidates in 4 rows locked into 4 columns. I think if you had noticed this, it would have cut your solve time by half. It would be great if one of the setters who follow your channel could create a puzzle that included an X-wing, a swordfish, and a jellyfish, that required you to find them in order so you could demonstrate how the same logic is applied to all three.

@jalsing 4 жыл бұрын

Late to the party, just catching up on this channel but wanted to say I solved this via the Jellyfish as well!! I saw the uniqueness trick above but wanted to try without using that.

@killroy42 4 жыл бұрын

I solve this surprisingly quickly, and didn't notice using anything fancy...

@CuratedPile 4 жыл бұрын

I'm an average solver, this one took me 12 minutes. Ran into 2 unique rectangles, both with 36 pairs on 3 corners and one extra candidate on the 4th corner, so direct solves. The puzzle collapsed with those. I haven't watched your solve yet, but I will. EDIT: watched the video. The 2 unique rectangles I hit were both a direct consequence of the swordfish on 3s and x-wing on 6s that you hit. I find unique rectangles a lot quicker than swordfishes, so I tend to use them often.

@JohnRandomness105 Жыл бұрын

10:00 At this point, I spot the jellyfish in both 6s and 3s in rows 2, 3, 6, and 8, the jellyfish that may have helped me solve the puzzle. 13:00 I went back to see why I spotted the jellyfish and not the X-wing. It was because the jellyfish was based mostly on penciled-in 6s and 3s. The X-wing was based on 6s elsewhere blocking the cells. In either case, 6s were ruled out of the exact same cells. 18:00 I might have spotted the swordfish in 3s had I spotted the X-wing in 6s. One advantage of the jellyfish was that 6s and 3s went together -- once I saw it, I saw it for both digits. Again, the same cells were ruled out of the 3s.

@jhattara 3 жыл бұрын

Before getting to the swordfish, I spotted that there was a 4x4 pattern of 3's that forced the 3's into the swordfish pattern *before* the x-wing was marked. Thus I got that 37 pair solved the moment the x-wing popped up, because I had already restricted 3's out of that square.

@lawrencekallal6640 4 жыл бұрын

Starting at 18.30, force testing a 3 or 6 in RC97 results in a 3 or 6 being forced into RC92 -- a conflict, so RC97 has to be the 7. That was enough to crack the puzzle open.

@RandomBurfness 4 жыл бұрын

I solved this by finding a swordfish on 3's and then abusing the ever living hell out of uniqueness. Now let's see if Simon uses uniqueness in his solve!

@chookingvid 4 жыл бұрын

This was my first time spotting an X wing on my own, but that wasn't enough to make any progress.

@Djn2611 3 жыл бұрын

There's a jellyfish on both 6's and 3's

@57thorns 4 жыл бұрын

Took me 65 minutes, in the end I did have a 6 instead of a 5 in one square, I believe it was a late error. Lots of X-wings and at least one uniqueness did it for me. A uniqueness chain of 6 2/6 squares (rather 5 eliminating the 6th). Seeing the simple 36 uniqueness that FF Fanatic pointed out I have no idea where I got lost, I know I saw that one. Except perhaps I did not get the 1 immediately for some reason.

@tonyawright6020 4 жыл бұрын

I found the x-wing on the 6s but missed the swordfish. I combined the x-wing with the limits on 1s to work out how to narrow out some of the 3s enough to give me the solve, but would have been a lot quicker if I'd found that swordfish. I have yet to find a swordfish on my own. :(

@gposchman 4 жыл бұрын

I was finding x-wings specifically rows 3 & 8 columns 1 & 3. Row 3 with a 36 pair and column with a 36 pair. R3C1 had 136 and I went with the one on uniqueness. Once conquered that x-wings on the right led me through to the solution. We won't talk about the time, I'm the turtle slow and steady.

@sarsoar 4 жыл бұрын

I feel I got lucky and saw that naked 36 in r8c3 early on and then the uniqueness trick for the 1 you mentioned. And then its easy from then on like you said.

@insectbah 3 жыл бұрын

I always feel better when the place I get stuck is where Mark bifurcates and Simon slows down

@KCML82 4 жыл бұрын

I'm not even close to your level Simon, but I facepalmed really hard @ 21:57 , lol

@rilian226 4 жыл бұрын

21:25 you had the bottom left 3x3 filled w/ all but one #. You later solved it a harder way but it could have been filled immediately which would have solved 3 more squares immediately...

@grahamfisher307 3 жыл бұрын

I was wondering how long it would take to find the 5 & 8 pair in R1C7 & 8. I used uniqueness also.

@javabeanz8549 4 жыл бұрын

After the X-Wing on the 6's, R8-C1 became 136 candidates, so rows 3 and 8, with columns 1 and 3 allowed application of Uniqueness. That broke this puzzle for me.

@goldenera7090 4 жыл бұрын

@11:05, I think we can use uniqueness to get 1 in row 8 col 1 and the puzzle collapses from there....

@wolf3522 4 жыл бұрын

I used that one as well

@RoderickEtheria 4 жыл бұрын

I ended up bifurcating and getting lucky the first time I messed with the 8s.

@Wecoc1 4 жыл бұрын

Where is this puzzle from?

@CrackingTheCryptic 4 жыл бұрын

Hard to tell. The email just included a list of digits. I've asked the sender. Why, don't you like it?

@Qazqi 4 жыл бұрын

@@CrackingTheCryptic Equally possible to reallly like it and want more. I actually loved how many naked pairs were involved in my solve-they kept coming.

@rabidsamfan 4 жыл бұрын

15 minutes and no wings. Nice puzzle but I will have to watch the video to see why you gave it that title. (Edit: I think my habit of watching for uniqueness made a difference, but I also used the triple in the top left box to work out the pairs in the top row right off the bat, which may have helped.)

@lewiswegner2339 4 жыл бұрын

22m 09s

@BryanLeeWilliams 4 жыл бұрын

38 minutes.

@wowwee8562 4 жыл бұрын

21 minutes

@immabreakaleg 4 жыл бұрын

I had to bifurcate too.... 30 mins

@michaelbaker9347 4 жыл бұрын

Good Lord this one was crazy. took me an hour and a half to solve, probably with a bit of luck because i dont quite understand Y wings or bent triples. Edit: upon watching this video, i was completely oblivious to the x wing on 6s and swordfish on 3s