Ennead

A calm, classic sudoku with pencil notes and a quiet timer.

Ennead deals uniquely-solvable sudoku puzzles in three difficulties, with pencil notes, live conflict highlighting, hints and a gentle timer that tracks your best runs. Built end-to-end with AI as a single self-contained HTML file that runs fully offline — the source is downloadable and MIT-licensed. No login, no ads, no tracking.