GridMewCandidate marks that keep your reasoning clear
Use × as a record of exclusions, and distinguish notes from fixed facts.
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A blank cell is a possibilitySwitch tools before you actDo not turn a note into an assumptionApply the ideaOriginal exampleCheck your understandingOriginal GridMew lesson · Updated 16 October 2026
Learning goal: Attach a rule to an × mark and remove unsupported notes instead of treating them as facts.
A blank cell is a possibility
A blank cell is a possible cat location until a rule excludes it. An × is your note that the location is unavailable. It does not change the puzzle rule or certify that your deduction was correct. Leaving a cell unmarked is safer than crossing it out because it merely looks unlikely.
After placing a cat, review its row, column and region, then its eight immediate neighbors. Each exclusion should have one of those reasons. In the example below, follow the first explained placement and compare its affected cells with your own notes.
Switch tools before you act
Place cat and Mark × are separate modes. Both work with one tap or click; right-clicking and double-tapping are not required. On a keyboard, arrows move focus, Space uses the selected tool, and X toggles a note directly. The visible focus border tells you which cell will change.
Notes are saved with the current game and participate in Undo and Redo. Undoing an exclusion is a normal correction, not a penalty. The game does not award a benefit for adding as many × marks as possible.
Do not turn a note into an assumption
If you cross out a true candidate accidentally, the board may appear to have no place for a cat. Recheck the reason for the most recent notes before guessing. GridMew’s logical hint engine derives steps from rules and cats rather than treating all your notes as proven facts.
In the custom solver, × notes are ignored by default. Turn on Treat × notes as exclusions only if you deliberately want to solve under those assumptions. A no-solution result then may be caused by a note rather than by the original regions.
Apply the idea to gm-5-0007
r2c3 means row 2, column 3, counting from the top left.
In gm-5-0007, E is the lone cell r5c5. After that cat, column 5 is occupied, so B is left with r2c4. The example shows the position before this second placement. You can reconstruct the exclusions from the first cat rather than trusting unexplained crosses.
After placing r2c4, mark r3c3 because the cells touch at a corner. An × at r3c2 would need a separate justification: it is not a neighbor of r2c4. Keep a short mental reason such as “column 5,” “filled B,” or “corner of r2c4” for each new group of marks.
A real step from gm-5-0007
region B has only one remaining candidate: row 2, column 4. Every other cell is excluded by earlier placements or deductions. Place the cat here.
Check your understanding
Should r3c3 remain available after you place the forced cat at r2c4?
Show the explanation
No. It is one row below and one column left, so it touches the cat at a corner. This exclusion follows from the placement, independently of any notes you made earlier.