Translation guide
A number-placement puzzle where you fill a 9×9 grid so that each column, row, and 3×3 subgrid contains all digits 1–9.
Referring to the game or puzzle called sudoku
The standard Japanese term for the puzzle. Literally 'number single' (i.e., digits must appear singly).
毎朝、数独を解いています。
I solve a sudoku every morning.
Abbreviation of 'number place', a common alternative name in Japan. Slightly more casual.
ナンプレの雑誌を買った。
I bought a sudoku magazine.
Describing the activity of doing a sudoku puzzle
The most natural way to say 'solve a sudoku'. 解く means to solve a puzzle or problem.
通勤中に数独を解くのが好きです。
I like solving sudoku during my commute.
More general 'do/play sudoku'. Less specific than 解く but perfectly natural.
暇なときに数独をしています。
I do sudoku when I have free time.