In these videos I share creative solutions to difficult Sudokus. These solutions mix imagination and intuition with reason and logic. I use a base method that allows me to see clearly all around the board. I call it the "only two cells" method. I mark places where there are only two cells in a given block where a given number can go. I find that this is sufficient to solve puzzles, and it really helps to have a clear board uncrowded with candidate numbers. [Update: Since starting this channel, I have learned that while I arrived at this method independently, it is actually known as Snyder Notation, after the solver who first practiced it, Thomas Snyder. Acknowledgments to him.] While developing these videos, I found myself moving into a further method, seeing Sudokus as nine interlocking number grids. This has enabled me to solve even more challenging and satisfying puzzles. The videos illustrate these methods.
(I am C.R. Smith, a longtime fan of Sudokus. Thanks for watching!)
There are 3 possible cells for entry of 7 in row 7 or column 6. Though your answer is correct, (column 2 row 7 or column 5 row 7?) It is not only getting the answer correct but also how you got it correct matters to lovers of sudoku 17. That was not explained.
As the comments on this video explain, in solving this Sudoku, I followed a particular strategy. It was to place numbers where they would generate the most further numbers of their own kind. As I say in the comments, "A 17-given puzzle is so sparse that the numbers have to come from somewhere. It is reasonable to expect that the puzzle may be 'programmed' to generate many numbers from a single one. So I would say that this is a technique that solvers should keep in their back pockets for situations such as this one in which it has logical, reasonable prospects of success." Admittedly this is different from the strategy of looking for definitive proof for the placement of each individual number. I certainly respect those who follow that strategy. But I also think that we can all find enjoyment and success with Sudokus in our own ways.
That cell is in the same block where there is already a 1,2,3,7, and 8, and it is in the same row where there is already a 4,5, and 6. So it can only be a 9.
