I don't understand the hidden signal... 6 could have always gone on the top left cell.of the top ri8 block... so why did you put in the left bottom cell of the block?
Thank you for your time and efforts. Kindly consider adding an explanation to the current "What is the Swordfish and the logic behind it. a method that tells us how to notice and why is.
I don't understand the logic of the first example. It's clear that if B2 is a 7, then A7 surely cannot be a 7. But it seems there is nothing that says that if B2 is a 2, then A7 cannot be a 5. How do you arrive at the conclusion that if B2 is 2 then A7 must be 7?
For anyone who stumbles across this, it all makes sense if you remember that the 7s in each of the two columns in question are their column's only candidates for a 7.
50 comments -all positive so far, WHY no one che ked the 👍like button? I’d really like to know. I haven’t solved this puzzle yet or finished video, I’ll check back after.
At 15:14 you said the diagonals must be true. But at 16:26 you didn’t fill out the bottom right as a 1. That would have chained a lot of numbers together. Was there a reason not to do that then?
Summary *Some term abbreviations for brevity* V = Vertical conjugate pair H = Horizontal conjugate pair H1 and H2 refer arbitrarily to the two points in the pair, likewise for V1 and V2. H1 & V1 meet in the same square, H1 ≠ V1. Intersection of H2 & V2 can elim. that num as a candidate
Sudoku has very much to do with math, see Sudoko techniques and algorithms. Watch some numberphile videos about it. Still, I see what is meant with "Sudoku is not math"
The Snyder notation was helpful. I recently moved up to the medium puzzles, but was keeping it all in my head and not using any kind of notation. This has shaved down my time and made it easier. :)
Missed little nines in block five, row five, which gives a big nine in block six, row four. Available since timestamp 03:46, but of course, you can't be everywhere at once, and it gets solved later anyway.
I was so stuck...all that was left in the puzzle were pairs, triplets, quads, quints, septs in every direction and within all blocks...nothing to eliminate! Also no x-wings, x-y wings, xyz wings, w-wings, and no skyscrapers that could eliminate any little number. Then I happened upon this video. Thank you so much for the perfect explanation....one empty rectangle solved the puzzle completely. I have to start always looking for empty rectangles in every puzzle I do so that I will always have it in my arsenal of techniques.
I would appreciate greatly if you would start doing the New York times medium crossword puzzles online. I used to be able to do them but they seem to getting harder
I see. So it wouldn’t work if the squares were not aligned on the cell with an offset/nonalignment since the only intersections would come from cells that were already guaranteed not to have that number
