As I looked over the "givens" for this Sudoku, I noticed a place where two of only three possible numbers (1, 2, 7) had to go in two cells that were in the same row and block. I then noticed that the other instances of those same three numbers elsewhere in the grid were positioned in such a way that the three possible combinations (12, 17, 27) could be efficiently tested by trying them by pairs in those two cells and putting one number from the pair in two corresponding cells in the block below. This typically also placed the other number from the pair in two corresponding cells in the block above. By this means the incorrect combinations were quickly falsified.
Once I found a combination that “took” (2 and 7), I added the remaining number (1) to the two cells above. Again given the distribution of these three numbers throughout the puzzle, it seemed probable that this placement would either be efficiently falsified or it would solve the puzzle. And it did solve the puzzle, though some elaborate tactics were required that I hope viewers will enjoy watching.
This puzzle, Trompe l’oeil, turned out to have the same basic design as its fellow Sudoku named after an optical illusion, Fata Morgana (video #29). And both of these Sudokus are actually transpositions of the design found in Platinum Blonde (video #14), Golden Nugget (video #15), Red Dwarf (video #16), and some other puzzles for which there are videos on this channel. In each case, there is a place on the board where two of three possible numbers must go in two cells in the same block and row or column. Other instances of those three numbers are placed strategically around the board in such a way that combinations of two can be tested, wrong ones efficiently falsified, and the right one followed to the solution. There is always a key moment where the third number, the one not in the original pair, is introduced in a corresponding location. These are all considered to be very difficult Sudokus, and yet they have an elegant and consistent underlying structure that makes their solutions appealingly straightforward.
Trompe l’oeil was created by a Sudoku designer and theorist who went by the name of tarek on player forums. I have no further information about this person, but I certainly admire his or her contributions. Thank you.
8 сен 2024
