A daily sudoku built for e-ink tablets and a stylus. Three puzzles unlock every day at local midnight — easy, medium and hard — each graded by the solving techniques it actually needs rather than by its clue count, and each keeping a tick once you solve it. Solving a harder one ticks off the easier ones with it. Tap a cell and tap a number to fill it in; write anywhere on the page with the pen and the handwriting is saved alongside the puzzle. Works offline, keeps your streak on the device, and has no accounts, no ads and no server.