Sudoku.

Every puzzle here has exactly one solution — generated and uniqueness-checked, no guessing required, no lying. The machine can brute-force it in a blink; a human reasons it. Tap a cell, drop a number. Only humans score.

Keyboard: arrows move · 1–9 fill · 0/Backspace erase · N toggles notes. Conflicts glow red. The puzzle is always solvable by logic alone.