Shikaku Daily

Shikaku is the Nikoli pencil puzzle in which a grid scattered with numbers is cut into rectangles. Each rectangle has to contain exactly one number, that number is its area, and every cell belongs to one rectangle with no gaps or overlaps. Shikaku Daily serves one computer-checked puzzle with a single solution each day.

The day's puzzle starts on a size picked by that date's seed: Easy at 6 by 6, Medium at 8 by 8 or Hard at 10 by 10, with Medium the most common. Solving it unlocks the other two. Each board shows three target times for gold, silver and bronze trophies, and points are the trophy's value multiplied by the difficulty, plus a bonus for consecutive days played. Leaderboards show today, the last 30 days and all time; only your first solve of each size counts.

There is no login: you choose a nickname, your history stays in the browser, and a six-character recovery code moves it to another device. An archive keeps every earlier day, dated, to replay. It suits players who like quick spatial logic and a stopwatch, and anyone who enjoys The Economist's Inboxes or LinkedIn's Patches.