Crossword rival? (6)
I believe the answer is:
sudoku
(Other definitions for sudoku that I've seen before include "Popular number puzzle" , "Popular logic-based puzzle" , "Japanese number puzzle" , "filling boxes" , "Numeric puzzle" .)
I believe the answer is:
sudoku
(Other definitions for sudoku that I've seen before include "Popular number puzzle" , "Popular logic-based puzzle" , "Japanese number puzzle" , "filling boxes" , "Numeric puzzle" .)