It can be solved by deterministic finite automation on boards of a finite size.
Designed by Howard Garns, it first appeared in America in 1979 though didn't catch on until recently. It can be solved by deterministic finite automation on boards of a finite size. First published in Dell Pencil Puzzles and Word Games, it didn't take its current name until it became a hit in Japan. That name is an abbreviation for a phrase which means "the digits must remain single." For 10 points what is this puzzle game in which the digits one through nine must be placed in a 9X9 grid with 3X3 subgrids?
Designed by Howard Garns, it first appeared in America in 1979 though didn't catch on until recently.
{sudoku}