9×9 · Medium to expert
Arrow Sudoku
The digit in each circle equals the sum of the digits along the arrow attached to it.
About arrow
What arrow sudoku feels like.
Arrow sudoku draws circles with arrows trailing from them. The digit in the circle must equal the sum of all the digits the arrow passes through. Because a single cell holds at most 9, the arrow's digits are tightly limited. Standard sudoku rules apply on top of the arrow sums.
Rules
- Standard sudoku rules apply: each digit 1–9 appears once per row, column, and 3×3 box.
- Each circle contains a digit equal to the sum of the digits along its arrow.
- The circled digit is at most 9, so long arrows must use small digits.
- Digits may repeat along an arrow only if normal sudoku rules still allow it.
History
Arrow sudoku is a modern favourite of the online variant-sudoku scene, often combined with thermometers and other constraints.
- Key rule
- The circled digit equals the sum of the digits along its arrow
- Difficulty range
- Medium to expert
- Tips
- A two-cell arrow summing to a circle means small digits: e.g. 3 = 1 + 2.
- A three-cell arrow forces very small addends, since they must total at most 9.
- The circle can never be 1 if its arrow has two or more cells (the minimum sum is 1+2=3).