by Ed Glysson
(Morgan Hill, CA.)
Sudoku –54 Clues in Five Minutes
This methodology is easy to utilize, but the explanation is wordy so stay with me. Start the Clock!
There are 9 Squares (each containing 9 spaces) in a Sudoku template, and each Square can be harvested for 6 clues that extend to other Squares; so total, yes that’s 54 Clues. (The above Sudoku layout can be used to help visualize the following explanation. I identify the Squares from 1 to 9, starting from the top left Square 1 and moving to the right, then wrapping to Square 4, and wrapping again to Square 7.)
OK… our discussion will be limited to Square 1, but can be extrapolated to all Squares. If you have puzzling materials (see my other article), use them to follow along the discussion; marking the spaces identified. Also, if you have ANY finished Sudoku game, you can use that to help visualize the discussion.
In Square 1 there are nine spaces which can be visualized as groups of three. There are three rows of three spaces and three columns of three spaces (notice the overlap, it’s needed for our task).
Arbitrarily starting with the first two columns of three spaces in Square 1 (the A’s in the example above) , one can observe that these are the same entries as in the A spaces identified in Squares 4 and 7.
Examining further one can observe that the B’s in Square 1 will occupy the spaces identified as B’s in Squares 4 and 7. (Yes… again there is overlap within Square 1, ignore it, it’s not important.)
Continuing the observations with C, D, E, and F the puzzler can conclude that there are 6 perspectives for the entries in Square 1 (and in fact for each Square, resulting in a total of 54 Clues).
Notice that the Square 1 discussion directly relates to Squares 1, 3, 7, and 9 as they are all corner squares. Squares 2, 4, 6, and 8 are all middle squares so you will have to extrapolate the discussion a bit based on their position; as well as Square 5 holding down the center of the puzzle template.)
I recommend that you study completed Sudoku games, any game will do (Easy to Hard) and practice observing these groupings of entries. Once 54 Clues is mastered your Sudoku resolution skills will step up at least one notch.
Did we make the Five Minute goal? Hopefully yes, and it was time well spent.
Ed Glysson, Morgan Hill, CA. Summer, 2014