Start with narrow regions

Small does not automatically mean solved

A region with few cells is a good place to look because it starts with fewer candidates. A one-cell region forces its cat immediately. A two-cell region still needs another reason to choose between the two. Shape narrows your attention; it does not permit a guess.

Check whether fixed cats have already filled the rows or columns passing through that region. Then check immediate neighbors. The smallest region is not always the one with the fewest surviving candidates after these constraints are applied.

Follow a long thin region

If every candidate of a narrow region lies in a single row or column, it locks that line even before a precise placement is known. Exclude cells outside the region on the line, then look for consequences in neighboring regions.

For the board below, compare the connected lettered areas and count their cells. Region boundaries and letters identify shape without relying on color. The actual forced step beneath the diagram shows whether the starting advantage comes from a small region or another completed group.

Do not overlook connectivity

Two patches with the same color may appear separate in a screenshot or a poorly drawn custom board. GridMew requires each region to be connected by shared edges. A corner contact alone does not join two patches into one region.

If the editor reports a disconnected region, correct the painted cells before asking for a solution. A beautiful-looking narrow shape is not useful evidence until the board’s region structure is valid.

A real step from gm-5-0001