Mykola Krylov

The Big Book of Logic Puzzles - Heyawake 400 Hard (Volume 58) Mykola Krylov

Heyawake (from Japanese, "divided rooms") is played on a rectangular grid. The grid is divided into rectangular "rooms". Some rooms may contain a single number. These rooms must have the designated number of cells painted black. Other rooms may have zero or more cells painted black. Black cells must not be orthogonally connected. All white cells must be interconnected. A line of connected white cells must not connect more than two rooms together.