GridMewStart with narrow regions
Use region shape to focus attention while checking all row and column constraints.
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Small does not automatically mean solvedFollow a long thin regionDo not overlook connectivityApply the ideaOriginal exampleCheck your understandingOriginal GridMew lesson · Updated 16 October 2026
Learning goal: Use a small region as a place to inspect, while requiring an actual reason to choose its cell.
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.
Apply the idea to gm-5-0008
r2c3 means row 2, column 3, counting from the top left.
E in gm-5-0008 consists of r4c1 and r5c1. Both are in column 1, but that fact alone does not distinguish them. The fixed cat at r4c4 already occupies row 4, removing r4c1 and forcing E at r5c1.
Now update column 1 across the whole board. Row 3 becomes restricted enough to force r3c2. This example shows why “start with a small region” is an attention strategy, while the filled-row argument is the actual proof.
A real step from gm-5-0008
region E has only one remaining candidate: row 5, column 1. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Check your understanding
Could you choose either E cell because the region has only two cells?
Show the explanation
No. The upper cell is already excluded by row 4’s fixed cat. Before that information is applied, region size alone would not justify choosing either cell.