Hey Simon i really appreciate the way you take time to explain things that are dead simple to you but certainly definitely not at all simple to me !. From watching your videos I reckon i have a fair chance of spotting an 'X' wing, I'd never heard of one before, maybe now i might be able to finish the 'difficult' ones in the Express ! yeah i know they're basic to you but i'm learning. THANKS.

I finally see the tremendous value of X=wings having watched this video. Now to put it into practice! Thank you!

So I always try to solve nikoli puzzles without guessing (aside from the time trials) as there is inevitably something clever to be found and so why deprive myself of that? To remove some of the mystique, I had started the puzzle previously, hit the wall, had to go off to do something else before returning to it a second time. That's why a lot of those placements go in quite quickly at the start. There is an interesting point with x-wings I thought I'd mention. Where they partially "overlap" - such as with the 1s and 5s, or else with the 3s and 6s which you can also see in the video, you can in fact turn this pair of cells into a pair, where no other candidates can appear. Try it!

May be the best I’ve watched to date. It made sense to me.

I constructed the X-Wing but only because I look for where numbers can only occur in two places in columns and rows as well as boxes. Both pairs of 7s follow from this approach but I didn't construct it so early on. Similarly the second X-Wing of 1s follows from observing the only two places for 1s in columns one and six. This is why I prefer to extend Snyder technique to look for the column and row pairs in addition to the box pairs. It doesn't make me any more successful, it's just the technique I developed before I had even heard of Snyder or looked at KZfaq solving techniques. About 40% of the time I end up with a puzzle full of mismatched pairs but your video on the "Bug" has convinced me that such an end game usually only has three situations, all of which are solvable. Apart from X-Wings I am simply hopeless at recognising most of the other patterns that lead to quicker solutions and I certainly didn't take advantage of the combination of X-Wings to resolve the 1,5 and 7 in column two. The whole puzzle took me something under an hour and a half but I can't really tell because I fell asleep for a few minutes. If I can I will have a look at deu's solution to compare it to Tom's.

Really enjoyed this!!! Thank you

Very useful ideas man Thank you

I know you did this four years ago, I am a beginner at playing and I am finding these basic ideas interesting.

wow absolutely fantastic. thanks for sharing

I tried it, but got lost in there somewhere. Going to have to start over again and see if I can figure it out. The X-Wings I get now, pairs in two columns or two rows, lets you eliminate any going the perpendicular direction. But the Swordfish, I still need to study that pattern, I don't yet understand it just yet.

This took me a bit over an hour, without bifurcating, and that's with the massive clue of the title of the video. I actually lost count of how many x-wings I needed to use during the solve. No Swordfish, although I did use some quadruples. Watching the video I see that I started in the same place as Tom, with the 7s, 1s and 5s. A very chewy puzzle! Nice! I may run through it again and try bifurcating, just to see how long it takes.

When the "Swordfish" shows up, you mentioned that you had a video that deals with that pattern, but I can't find it by looking in the titles. Do you happen to remember which video that is in?

Fantastic!

I solved it in 16:36 Lots of X-Wings, hidden triples and such. I did not find any advanced stuff. It was still tricky, because each step revealed another hidden thing. Great puzzle.

Very interesting observations. How come you applied that logic only to column 2 and not the others? What about column 3?

Wonderful👏👏

Why can’t the 7s go into column 8 when setting up the x-wing?

7:10 for me after importing and building the candidate list, with no hints given. Was able to crack this using a few X-wings and a swordfish, nothing more advanced.

I still can't finish the whole puzzle after putting in ‘1’ in r2c1, r4c8, r5c2, r6c6; ‘5’ in r3c2, r4c5, r6c1, r7c6; ‘7’ in r4c2, r5c6. What’s the next number to put in?

I do not get it. There are other places 7 can go but we act like the 4 places are the only ones ?

Please improve your audio in future videos.

He should get to the puzzle quickly instead of talking n talking irrelevant things which have NOTHING to do with the sudoku at hand.