What makes Sudoku Logic different?
- Hints explain the next logic and technique instead of entering the next digit
- Technique pages revisit boards you actually encountered during practice
- Four progressive highlight levels reveal more relations around a selected cell
- Three sharing choices support collaboration: initial board, digits, or digits with memos
Basic Sudoku rules
Every row, column, and 3×3 box contains each digit from 1 to 9 once.
Memos and undo
Tap an empty cell again to use memo mode. A confirmed digit and hidden memos are kept together; erase the digit to reveal its memos again. You cannot add memos to a filled cell, and input or erasing can be corrected with undo and redo.
Selected-cell highlights
Expert: selected cell only
How hints work
Hints only explain the next logic when you ask. They never enter an answer automatically. When you explicitly request a hint in Practice mode, the app may asynchronously send the initial grid, confirmed entries, and next logic step as an anonymous example to improve technique explanations. Memos and account, session, or device identifiers are not sent or stored with server examples.
Practice and challenge
Challenge turns solving assists off; practice uses your saved settings.
Sharing choices
Share the initial board, current digits only, or current digits with visible memos. Choose the last option when a friend should see your current thinking.