Use every clue to partition the board into rectangles containing one matching area clue; the shipped board has exactly one checked solution.
Shikaku partitions a numbered grid into axis-aligned rectangles. Every rectangle must contain exactly one clue, and its area must equal that clue; rectangles may not overlap or leave any square uncovered. A clue of six might form one-by-six, two-by-three, three-by-two, or six-by-one depending on boundaries and neighboring clues. The generator enumerates candidate rectangles per clue and runs an exact-cover search, rejecting boards with multiple partitions.
Move to one corner, press OK to anchor it, then move to the opposite corner and press OK again to place a rectangle. Selecting an existing region removes it for revision. Touch input performs the same two-corner gesture without requiring a precise drag. Reset clears every border but retains the area clues. Candidate outlines use distinct colors so shared edges and accidental overlaps are easy to inspect.
A legal rectangle scores according to its covered area, with chain bonuses for placing several non-overlapping regions. It contributes to progress only when it encloses one clue whose number equals the area. Overlapping, clue-free, or multi-clue proposals are rejected rather than corrupting the board. The final award arrives when all cells belong to exactly one valid rectangle, and the strongest completed total is saved locally.
List each clue's possible dimensions and positions. Boundary clues have fewer placements, and a candidate containing another clue can be crossed out immediately. Find cells reachable by only one candidate rectangle; that candidate is forced even if its clue still has alternatives. After placing it, remove every overlapping candidate from neighboring clues and repeat. Large rectangles often become clear only after several small boundary regions are fixed.
On phones, the anchor-and-confirm method is more reliable than drawing a thin outline with a finger. Directional and OK buttons retain large touch targets, while the canvas expands across portrait and short landscape viewports. Debug mode places certified regions one at a time and restarts after the covering is complete. render_game_to_text records anchors, rectangle bounds, clue-area checks, uncovered cells, overlaps, score, and exact-cover count.
List each clue's possible dimensions and positions.
On phones, the anchor-and-confirm method is more reliable than drawing a thin outline with a finger.
Shikaku: A legal rectangle scores according to its covered area, with chain bonuses for placing several non-overlapping regions
Use every clue to partition the board into rectangles containing one matching area clue; the shipped board has exactly one checked solution.