Shikaku Techniques

Three techniques solve every Shikaku puzzle on PeerPuzzles. Only one fit places every rectangle; overlap and only one number can reach clear the way for it on the bigger grids. Each page shows its technique on the same 12×12 puzzle from the game, at the moment it’s first needed, so you can follow one solve from page to page.

Hard level 2, the 12×12 every technique page follows. It takes 28 steps and needs all three techniques.

How many of the game’s levels need each one, out of 50 in each track:

Technique	Easy 7×7	Medium 10×10	Hard 12×12
Only one fit	50	50	50
Overlap	31	48	50
Only one number can reach	0	9	50

“Needs” means the hints, which always use the simplest technique that works, used it at least once. When none of these works, the hints fall back on what-if (try a rectangle, and see whether some number runs out of room), but none of the game’s levels needs it. For all three in one place, with another worked puzzle, see how to solve Shikaku.

Hard level 2, solved.

Guides

Shikaku: Only One FitThe most used Shikaku technique: a number with only one rectangle left that fits gets it. How to list a number's rectangles, with a real example.
Shikaku: OverlapWhen every rectangle a Shikaku number could be shares some squares, those squares are its: no other number can use them. With a real example.
Shikaku: Only One Number Can ReachEvery Shikaku square belongs to some rectangle. A square only one number can reach must be in that number's rectangle. With a real example.