Heyawake (meaning 'divided rooms' in Japanese) is a Nikoli logic puzzle invented in 1992. The grid is divided into rooms by thick lines. Players shade squares black according to numerical room quotas while following adjacency and corridor rules.

Can two black squares touch in Heyawake?

No. Black squares cannot share a horizontal or vertical edge. They may only touch diagonally at their corners.

What is the two-border corridor rule in Heyawake?

A straight uninterrupted horizontal or vertical line of white cells cannot cross two or more room boundaries. That means a white beam can enter at most two rooms before a black cell must interrupt the line of sight.

What if a room has no number clue?

Rooms without a number can contain any number of black squares (or zero), as long as all other rules (adjacency, white connectivity, and the corridor limit) are obeyed.

Heyawake (meaning 'divided rooms' in Japanese) is a Nikoli logic puzzle invented in 1992. The grid is divided into rooms by thick lines. Players shade squares black according to numerical room quotas while following adjacency and corridor rules.

Can two black squares touch in Heyawake?

No. Black squares cannot share a horizontal or vertical edge. They may only touch diagonally at their corners.

What is the two-border corridor rule in Heyawake?

A straight uninterrupted horizontal or vertical line of white cells cannot cross two or more room boundaries. That means a white beam can enter at most two rooms before a black cell must interrupt the line of sight.

What if a room has no number clue?

Rooms without a number can contain any number of black squares (or zero), as long as all other rules (adjacency, white connectivity, and the corridor limit) are obeyed.

Nikoli Classic • Divided Rooms

Heyawake (Divided Rooms)

Q: Must all white cells be connected?

Yes. All unshaded white cells must form a single continuous orthogonally connected network across the entire grid.

Divide and deduce! Shade black cells to meet room quotas without letting unshaded white rays pierce across two or more room dividing walls.

5x5 Divided Rooms5x5 Grid • 5 Divided Rooms

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0 black cells

Click Tool:

Thick lines = Room walls • Left click: markWhite ray spans ≥ 2 room borders

Surveying chamber partitions...

Heyawake Rules & Chamber Mechanics

Published by Nikoli in 1992, Heyawake (“Divided Rooms”) tests spatial partitioning and line-of-sight constraints:

1. Room Clue QuotasA number in the top-left corner of a room indicates exactly how many black cells are in that room. Rooms without clues can hold any valid count.

2. No Orthogonal Black AdjacencyBlack cells can NEVER share an edge. Placing a black cell immediately protects its 4 orthogonal neighbors as white.

3. Connected White OceanAll unshaded white cells must form a single continuous orthogonally connected network. No isolated rooms or dead-end pockets!

4. The Two-Border Corridor LawA straight continuous line of white cells cannot cross two or more room boundaries! A black cell must be placed to break the corridor.

Master Deductive Tactics

1. Clear Zero Rooms First

Any room labeled with a 0 clue can have zero black cells. Every single cell inside that room must be marked white immediately!

2. Breaking Long Corridors

Look across the grid for straight lines of three adjacent rooms. If a row or column passes through Room A → Room B → Room C, at least one of those cells must be shaded black to prevent a white ray from crossing two boundaries!

3. Maximum Room Packing (Checkerboard)

In a $2\times2$ room, the maximum number of black cells without touching is 2 (placed diagonally). In a $3\times3$ room, the maximum is 5. When a room has a maximal clue, the checkerboard pattern is immediately forced!

4. White Connectivity Bottlenecks

Never place a black cell in a narrow $1\times N$ doorway or corner corridor if doing so would sever a room from the rest of the puzzle grid.

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