Entry cell
A white cell in a kakuro grid that the player fills with a digit. Each entry cell belongs to exactly two runs — one horizontal, one vertical — and must satisfy both.
An entry cell is a white cell in a kakuro grid — the cells the player fills with digits 1 through 9 to solve the puzzle. Each entry cell sits inside exactly two runs: one horizontal, anchored by a clue cell to its left, and one vertical, anchored by a clue cell above. The cell's digit must satisfy both runs' sum constraints and the no-repeats-within-each-run rule.
How entry cells differ from clue cells
The two cell types have fundamentally different jobs. Clue cells are part of the puzzle's structure — they carry constraints (the target sums) and they're never filled. Entry cells are part of the puzzle's answer — they hold the digits the player produces. The kakuro analogy to Sudoku has clue cells corresponding to the grid's borders or givens (structural information, fixed) and entry cells corresponding to the unsolved cells (the cells you place digits into).
Each entry cell's degrees of freedom are a digit from 1 to 9, narrowed by the two runs' targets and by the digits already placed elsewhere in those runs. Most entry cells start with several plausible digits and narrow as the surrounding runs resolve.
Why "entry cell" rather than just "cell"
The naming distinction matters because kakuro literature uses cell loosely. White cell is sometimes used; entry cell is the more precise term that emphasises the active role — the cells where the player makes entries. Some references use cross cell or square, but those tend to obscure the structural role.
A practical effect of the naming: when a kakuro article or technique entry says "every entry cell sees two runs," the meaning is unambiguous. Cell alone could mean entry or clue; entry cell specifies which.
The cell-and-run dual
Kakuro reasoning often runs along the cell-versus-run axis. Some moves look at a cell and ask which digits can fit given the run constraints intersecting at that cell — that's the cross-reference family of moves. Other moves look at a run and ask which combinations can fill it given the cells available — that's unique sum and the sum-combinations lookup.
The two perspectives are dual. A solved kakuro answers both questions consistently for every cell and every run on the grid.
See also
- Kakuro— A Japanese number-placement puzzle. Cross-sums act like a crossword grid; players fill white cells with digits 1–9 so each run sums to its target without repeating a digit.
- Run (kakuro)— A horizontal or vertical sum-segment in a kakuro grid. The white cells from one clue cell to the next, which must sum to the clue's target without repeating a digit.
- Clue cell— The dark cell in a kakuro grid carrying the target sums for the runs extending from it — usually one or two numbers separated by a slash.
Read more
- Meet Kakuro
An introduction to Kakuro — what it is, how it differs from Sudoku, and why people who like number-logic puzzles often end up preferring it.