Shikaku
Expert
00:00
Classic
Expert Shikaku — what to expect
Expert takes hard’s reasoning to a 10×10 board and adds one step on top. Sometimes a clue has several rectangles left and all of them cover the same cell. That cell belongs to the clue already, before you know which rectangle is right, and claiming it rules out every other clue that wanted it. Those are what break a board open where plain forcing stalls.
How to play Shikaku
- Divide the whole grid into rectangles. Every square ends up inside exactly one of them.
- Each rectangle contains exactly one number.
- That number is the rectangle’s AREA — how many squares it covers. A 6 can be 1×6, 6×1, 2×3 or 3×2, and nothing else.
- So a 1 is its own square, and a prime number can only be a single strip.
- Start where there is no choice: a number whose rectangle fits only one way, usually against an edge or a corner.
- Two numbers can never share a rectangle, which rules out a great many shapes before you try them.
- Every puzzle has one solution, reachable by logic alone, and every board has a move you can make from the empty grid.