Shikaku (shikaku.ch)

About Shikaku (shikaku.ch)

Shikaku asks you to divide a grid of scattered numbers into rectangles. Every rectangle must contain exactly one number, the number is the rectangle's area, and every cell has to be covered once. A 6 can be a 1 by 6 strip or a 2 by 3 block; a 1 is a single cell.

The site's daily puzzle is a 10 by 10 grid, dated at the top and the same for everyone. Pressing Start begins the clock, and a solved grid posts your time to Today's Leaderboard, which shows each player's flag beside their time. The page keeps your streak, best time and number of puzzles solved, and a share button copies your result. The archive replays earlier days; those replays are not scored.

Outside the daily there is unlimited play in four sizes, from 5 by 5 up to 25 by 25, and a long strategy guide. The site is a side project by Juulian from St. Gallen, Switzerland, free with no account or app. It suits anyone who wants a short, quiet logic puzzle with a stopwatch, and fans of The Economist's Inboxes who want a second grid a day.

How to play Shikaku (shikaku.ch)

1. Open shikaku.ch and press Start on today's daily puzzle.
2. Drag across cells to draw a rectangle whose area equals the one number inside it.
3. Click a single cell to place a 1 by 1 rectangle for a clue of 1.
4. Click or right-click a rectangle to erase it.
5. Cover every cell correctly to stop the clock and post your time to the day's leaderboard.

Screenshots

Tips

• Start with the primes: a 2, 3, 5 or 7 can only be a straight line.
• Clues in corners and along edges have fewer shapes that fit; place them early.
• Large numbers in open space are often forced once the small clues around them are placed.

Questions