It dates back to New York in 1979. That's right, Su Doku is not Japanese!
But it is great. Two years ago, I didn't know it. But since then, Su Doku has burst out of nowhere, becoming a little more prominent every month. Locally, the NY Post introduced it, with two new puzzles every day, one easy and one hard. The NY Daily News recently followed suit. The Times still does not have Su Doku, but their crossword puzzle master Will Shortz has himself endorsed Su Doku and published books of Su Doku puzzles.
The other day, at the Barnes & Noble bookstore at 54th and 3rd, saw a table with 40 Su Doku books by the door, and more upstairs.
To complete a su doku puzzle, you must enter a numerical digit from 1 through 9 in each cell of a 9×9 grid made up of 3×3 subgrids (called "regions"), starting with various digits given in some cells (the "givens"). Each row, column, and region must contain only one instance of each numeral.
I've completed the " easy " puzzle three days in a row now. Next, the intermediate puzzle. Puzzles like this are ideal for subway riding- it engages the mind, but not too much. I like Su Doku. It's fun.