Advanced Sudoku: Making X-Wings Simple

Рет қаралды 46,065

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: 56

@ambientIdeal 4 жыл бұрын

"The critical thing about an X-Wing, although we found this X-Wing in the rows,... the effect the X-Wing has is on the columns" I never realized how significant this point is in spotting x-wings. Perhaps the most difficult thing for me in X-Wings is not necessarily seeing the shape, but identifying how the X shape can affect the grid. This was such an excellent example for me because the hidden pair obfuscated the purpose of the X-Wing.

@s.scirocco4411 4 жыл бұрын

Usually, Cracking the Cryptic is far too cryptic! This time out was absolutely anything but. Best explanation of an X-Wing I've come across. Can't wait to put this into practice! Cheers!

@JohnRandomness105 Жыл бұрын

1:00 "A very early X-wing"? I found one in 6s very early. I continued floundering for a while, until I spotted two obvious 2 placements. (Later) and now I finished the puzzle. I was expecting more X-wings than that one. 2:30 "It's possible that it's right at the start." Not quite. You have to place a 6 first. After you finished the puzzle, I returned to a quote that caught my ear: 2:10 "... a sequence of X-wings." "... X-wing upon X-wing upon X-wing." It's nice that you agreed with me that the early X-wing was the only one needed in the puzzle.

@thezdbailey 4 жыл бұрын

If I ever figure out the X-Wing, this will be the video that got my brain moving in the right direction. Thank you for all your videos.

@FunWithPuzzles 4 жыл бұрын

Thanks. Its always interesting to learn new techniques from you.

@SamCoca 3 жыл бұрын

This was a fun one to solve. I found the X wing and it cracked the puzzle. Thanks for sharing.

@Socrates... 4 жыл бұрын

Will watch this a few times to learn, thank you

@wonkywombat 4 жыл бұрын

Another great explanation for us "newbies"

@davidwood639 3 жыл бұрын

Very good explanation of finding the x-wing and it's ramifications.......then you shot off like Lester Pigott out of the starting gates! - Left me at c.10 minutes! I'll keep plodding along!

@dr.ekbalenaya6057 3 жыл бұрын

I solved it by finding a swordfish for 6's in columns 2,4 & 7 .

@kurtstoudenmire6104 4 жыл бұрын

Wow, great solve! I got the x wing for the 6's in Rows 6 and 7 but I also got a Swordfish for 6's in Columns 2, 4, and 7. Even with that I still got stumped. Had to watch the video to see that it then resolved the 2-5 pair in the bottom right corner. Easy solve after that.

@maxfriis 4 жыл бұрын

Also had to look for instruction on this one. Very hard to spot that 2-5 pair.

@stevendavid5370 3 жыл бұрын

played along and I did it!

@rabidsamfan 4 жыл бұрын

32 minutes. And only because the title had me hunting that darn x-wing.

@guricomfotodeanime9704 3 жыл бұрын

23:33 here. Took me a while, but it was pretty fun!

@RandomBurfness 4 жыл бұрын

I guess I spotted the X-wing on 6's in the most round about way of spotting it. Namely, I spotted the corresponding swordfish on 6's in the complimentary rows, i.e. rows 4, 8 and 9, and then I saw the X-wing. :P

@JohnRandomness105 Жыл бұрын

Something similar happened to me on another puzzle. I found a jellyfish on 6s and 3s together, that helped me solve the puzzle. Then when I watched the video, Simon used an X-wing on 6s, then a swordfish on 3s. In both cases, the digits were ruled out of the same cells.

@Pyromonkey83 4 жыл бұрын

Yikes. Without me knowing that an X-Wing was involved from the title, this would have taken me AGES, and even with finding it, it took me a significant amount of time to realize which cells were actually affected by it enough to progress the puzzle. That is one of the most impressive "collapses" (it was still not exactly a full collapse) based on a single X-Wing I've ever seen.

@jk2l 4 жыл бұрын

Wont it be easier if you pencil every single possible values and deduct from there using naked pair/triple or hidden pair/triple?

@ericveneto1593 3 жыл бұрын

The 2/5 pair made the 8 immediately peaceable

@martinvanzyl747 8 ай бұрын

Many thanks for some very interesting videos. I hope you can help me with something. I'm looking for a sudoku program filters that will colour selected candidates and maybe let me draw in arrows for chains. Any suggestions will be greatly appreciated,

@ebutuoyjg 2 ай бұрын

left out the 3's in beginning

@thomaslong8401 2 жыл бұрын

I've advanced to NYT hard. But after watching this...I'M NOT WORTHY!!!!

@solfeinberg437 2 жыл бұрын

I think I can follow the logic, but about 10x slower - If I was doing it myself. And I'm frequently pausing to see if I follow him just watching him. Fun, though. We don't have to be as fast as Simon to enjoy Sudoku, thankfully.

@MyNarsa 4 жыл бұрын

took me 21min without looking or finding x-wings, got lucky and found a 25 pair in the bottom right box, and used a slot machine in 6's to exculde a few cells

@ernstraedecker6174 4 жыл бұрын

I spotted the X wing on cols 1 & 8, but didn't follow through on it. Being a computer programmer and a procedural guy, I took a completely different direction. Look at r6c8. If that is anything else but a 1, then 1 & 3 are in col 9 of block 6. Hence r1c8=3 and r2c8=1. But now r1c9 must be 2. Now r2c1=2 and r3c1=5. That forces r1c1=3. Error, bc r1c8 is already 3. Therefore r6c8 MUST be 1. The rest follows...

@rsmath1 4 жыл бұрын

Wasn't there an xwing 8 later in the solve (approx 14m20sec) with the 8s in col 4 and 5 rows 2 and 6?

@jonathananderson6634 4 жыл бұрын

Depends what you mean. This is my first time watching but I think normally, the fact that they only appear in certain rows or columns has to have an effect somewhere else on the board. In the original X Wing, the 6 could in theory have gone in a series of places in that column, however it was limited by the X Wing to being only in one of those two positions and that being mandatory. This meant you could rule the 6 out of other squares in that column, which might create other pairs or solve squares that were otherwise unsolvable. In the case of the 8s, the reason the X Wing shape exists is BECAUSE they have been ruled out of every other square in their respective rows and columns, so it does nothing for the solution. Hope that makes sense, honestly I did this more as a teaching tool more for myself than anything else

@FabianPyka 2 жыл бұрын

i wonder what a good time for a beginner would be

@ericveneto1593 3 жыл бұрын

It's ALSO shaped like the Star Wars ship of that name.

@bogbel1 4 жыл бұрын

xwing upon xwing upon xwing? You only found one. Does that mean there was only one? Or you didn't find the others? Anyway, it was really helpful.

@RO8s 3 жыл бұрын

No, he was referring to the following day's puzzle, for which this would be a good introduction...

@leoncarpenter958 4 жыл бұрын

The X-Wing forced the sixes into column two Row 8 and 9. That left the six in column 1 row 6 a naked single

@HULKEN1UP 4 жыл бұрын

No! you got lucky there :) The sixes in column 2 of box 7 do not exclude other sixes in column 2 as the 6 of the x wing is in that same box.

@leoncarpenter958 4 жыл бұрын

@@HULKEN1UP I've revisited the puzzle and as much as it pains me to say it you may be right. I think I might have missed the 6 in column 2 Row 4.

@rustysmith3565 4 жыл бұрын

I don't know how you spot things so fast, you must have a brain like a damn computer !!

@ssesf 3 жыл бұрын

Starts 2:38

@edensaquaponics1941 4 жыл бұрын

I spent 10 minutes and found the 6 and 8 pairs of pencil marks.

@milkom2021 3 ай бұрын

We were promised a X-Wing upon X-Wing upon X-Wing. I want a refund!

@bicyclemanNL 4 жыл бұрын

Wow, took you ages to find the 2, think i will stick to doing my own sodokus in future

@nksor3025 4 жыл бұрын

When you reach the point where the puzzle "opens up" and there are many different avenues to take to solve it, there is no such thing as a correct order except maybe for speed or ease's sake. He didn't take ages to find the 2, he was solving it in a different order than you.

@Coyotek4 4 жыл бұрын

Dang … I found the X-wing, but missed the resulting pair that was needed to continue.

@EntirelyPointlessContent 2 жыл бұрын

Yeah same. Found it nicely and tried to do some more advanced x-wing chains from it. Turns out it was just that pair all along to solve the entire thing. :( It's devious because neither of those cells look particularly exposed compared to anything else.

@krishnanvijaykumar8614 3 жыл бұрын

Very engrossing

@jimdetry9420 4 жыл бұрын

There were actually 2 sets of X wings on 6s at the beginning. You found the one in columns 1 and 8, but there was another in colums 2 and 7. That immediately cleared up the 6 in row 8 column 5.

@JaggerG 3 жыл бұрын

You got lucky. R8C2 could have had a 6, too. Suppose the 6 is in the top right. Then you have columns 2 and 4 unresolvable.

@Blubb5000 4 жыл бұрын

I didn't need a single x-wing technique to solve the puzzle. Hmmm....

@nigelm5777 4 жыл бұрын

If you didn’t know the early solve involved an X-wing, how would you proceed having only placed one 6? Surely that would not be a first thought.

@shane8037 4 жыл бұрын

Well I've seen ol' Simon stare at a puzzle for fifteen seconds and spot such things so he'd likely have done so again, but for us plebians I'm not really sure...

@RandomBurfness 4 жыл бұрын

While it's not a first thought, after being stuck for a very long time at an early stage of a solve it should become part of your sudoku solving machinery to hunt for X-wings.

@M4ke4l 4 жыл бұрын

i guess you prioritize your reseaches when you're stuck and not an expert, first obvious stuff then if you're blocked with those, you try to see x wings, if that doesn't help try bent triple, then swordfish etc...

@killroy42 3 жыл бұрын

I filled in a ton of digits quite quickly without any fancy techniques... then accidentally hit some key that refreshed the browser, and never managed again :(

@ElliottP2009 4 жыл бұрын

If there were supposed to be multiple X-wings in this puzzle, wouldn't it have been better to showcase them? Maybe do a full analysis of the puzzle off camera, then make the video showing us how to find them.

@RandomBurfness 4 жыл бұрын

You're confusing what's been told in the video. The multiple X-wings are for tomorrow's puzzle.

@ElliottP2009 4 жыл бұрын

@@RandomBurfness Ahh, I'm sorry, looking forward to it!