Shikaku

🎯 What is Shikaku?

Shikaku (also known as Shikaku of the Day) is the daily rectangle-division puzzle from shikaku.ch. Each day the puzzle drops a grid — usually 10×10 — with numbers placed in some cells. Your job is to divide the entire grid into non-overlapping rectangles such that each rectangle contains exactly one number, and that number equals the area of the rectangle (width × height).

The format is closer to a logic puzzle (Kakuro-style) than to Wordle. There are no guesses — you draw rectangles by dragging, and the goal is to find the unique solution. A daily streak and best-time leaderboard track your speed.

💡 How to Play Shikaku

Open shikaku.ch to see today's puzzle grid with numbers placed in some cells.
Identify the constrained rectangles first. A 1 in a cell means that cell is its own 1×1 rectangle; a number that equals the area of the only available space usually locks in a region.
Drag to draw a rectangle around a number. The rectangle must contain exactly one number, and that number must equal width × height.
Right-click (or click an existing rectangle) to erase it if you make a mistake.
Continue drawing rectangles until every cell belongs to exactly one rectangle.
Solve the puzzle as fast as possible — your time is recorded on the daily leaderboard. A new puzzle drops at the daily reset, and the Archive stores past puzzles.