Platinum Sudoku for Nintendo DS
Sudoku is the puzzle phenomenon from Japan, a game that looks like a
math problem, but is in fact a twisting puzzler. The rules are simple:
start with a grid consisting of nine three-by-three squares in which
some of the numbers are already supplied. Fill in the blank squares so
that each column, row, and three-by-three grid contains a number from 1
to 9 with none repeated.