GridMewBuild a chain of small deductions
Connect placements and eliminations without hiding a guess inside the chain.
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Each step needs its own reasonReason about every possible positionReview the chain in orderApply the ideaOriginal exampleCheck your understandingOriginal GridMew lesson · Updated 16 October 2026
Learning goal: Preserve the order of eliminations and distinguish a quota lock from a common-neighbor deduction.
Each step needs its own reason
A useful chain may start with a line lock, remove candidates, create a single, place a cat and then create another single. No individual step needs to reveal the final arrangement. The strength of the chain comes from maintaining a correct candidate set after each action.
Write down why the first removal is valid before using its consequences. If the first step was only a guess, several later forced-looking moves do not make the whole argument proven.
Reason about every possible position
Sometimes a group has two or more candidate cat positions and another cell touches all of them. Wherever the group’s cat eventually goes, that cell would be adjacent to it. You can exclude the common neighbor without choosing the cat first.
This is the unit-neighbors rule in GridMew’s verified traces. It uses the actual candidate coordinates, not a visual guess about nearby regions. The worked step below includes the earlier state needed to check those candidates.
Review the chain in order
The complete worked example preserves the sequence. Expand the solution only after following the exclusions and placements; an answer diagram alone cannot show which deduction was justified at the time.
On your own board, the staged hint first identifies where to look. Read its explanation, compare it with the current cells, then choose whether to apply it. You can keep solving yourself instead of automatically revealing the rest of the chain.
Apply the idea to gm-8-0005
r2c3 means row 2, column 3, counting from the top left.
gm-8-0005 begins with four locks: column 5 reserves E, row 6 reserves F, column 4 reserves C, and column 3 reserves A. Those restrictions leave row 1 with r1c3 and r1c5. Neither candidate is a cat yet.
Both row-1 candidates touch r2c4, so that cell can be excluded. Column 4 then has only r3c4. The first new cat is the result of the chain, not its assumed starting point. If you cannot justify one of the earlier locks, return to that before-state before continuing.
A real step from gm-8-0005
The cat in row 1 must occupy one of row 1, column 3; row 1, column 5. Each of row 2, column 4 touches every candidate, so none can hold a cat.
Check your understanding
Why can you remove r2c4 while keeping both r1c3 and r1c5 available?
Show the explanation
r2c4 touches either possible row-1 cat. Every allowed outcome conflicts with that cell, so it can be excluded without selecting an outcome.