Sudoku Puzzle Master

Sudoku Puzzle Master is the classic grid with the tools that make solving it comfortable. Nine rows, nine columns, nine boxes, and one rule that never bends: no digit twice in any of them. What changes between one puzzle and the next is how many numbers you are handed at the start, and the difficulty settings are settings for that.

The pencil notes are what separate a casual grid from a serious one. On an easy board you can hold the possibilities in your head; a few levels up you cannot, and jotting candidates into a cell is the only way to see the pair that solves a row. A hint is there when a board stalls, and the eraser undoes a digit you were too confident about.

How to play

Tap a cell to select it, then tap a number from 1 to 9 to drop it in. Start with the rows, columns and boxes that already hold the most digits, since those are where a single missing number is forced. When a cell has two or three candidates and you cannot choose between them, switch to pencil notes and write them all in rather than guessing. The eraser clears a wrong entry, and a hint will move you on if the board stops giving anything up.

Controls

Two taps place a number: one on the cell you want to fill, one on the digit from 1 to 9. The pencil notes mode turns those same two taps into small candidate marks instead of a final answer. The erase button clears whatever sits in the selected cell, and the hint button plays a move for you. A mouse click does the job of a tap on a computer.