#618 — Thu, Sep 10, 2026

What is a nonogram?

A nonogram — also sold as picross, griddlers, or hanjie — is a picture logic puzzle invented in Japan in the late 1980s. The numbers beside each row and above each column tell you the lengths of the consecutive filled runs in that line, in order, with at least one empty cell between runs. Deduce which cells are filled and which are empty. Our generated grids reveal abstract pixel patterns. No trivia, no vocabulary — just deduction, which is why the puzzle translated so easily from Japanese magazines to newspapers, Nintendo cartridges, and the browser you are using now.

How the daily puzzle works

Every day at local midnight a new board unlocks — the same one for every player, so times are comparable on the leaderboard. The date determines the size: 5x5, 10x10, 15x15, 20x20, or 25x25. Difficulty labels describe grid size, rather than measured solving complexity. Each board is generated fresh and verified to have exactly one solution reachable by logic alone, so you never have to guess. Solving today's puzzle extends your streak; anything you missed stays playable in the library, where replays never touch your streak. Prefer no calendar at all? Free play serves unlimited boards in any size.

Tips for today's medium grid

Mid-size grids are where the overlap method earns its keep: any clue longer than half its line forces cells in the middle before you know anything else. Open with an overlap pass on every row and column, then switch to the lines your new cells cross. When a line stalls, count its slack — clue lengths plus one gap each, subtracted from the line length — and spend your attention on the lines with the least room to move.

For the full toolkit — overlaps, edge logic, splitting, and the contradiction test — see the solving techniques guide, or start from the beginner's guide if this is your first grid.