🎯 How to play Arrow Sudoku
By Miguel Arechaga
Arrow Sudoku is a very elegant sum-based variant, popular in competitions and on channels like Cracking the Cryptic. Circles with arrows extending from them are drawn on the board: the circle's number equals the sum of the digits the arrow passes through. Here are the rules and a few tips.
What is Arrow Sudoku?
It's a standard 9x9 sudoku with several arrows drawn on it. Each arrow starts at a circle (the bulb) and travels through a series of cells. The extra rule is that the number in the circle must equal the sum of the digits in the cells the arrow passes through.
Rules and how to play step by step
- The sudoku rules apply: 1 to 9 without repeats in each row, column and 3x3 box.
- The number in the circle is the sum of the digits in the cells its arrow passes through.
- Digits can repeat along the arrow (it isn't a sudoku region).
- You start with some clue cells and fill in the rest with logic. Every puzzle has a unique solution.
Tips to solve Arrow Sudoku
- Two-cell arrows: if the circle is worth 3, the arrow can only be 1+2; if it's 17, only 8+9. The extremes give a lot to work with.
- The circle sets the minimum: an N-cell arrow forces the circle to be worth at least N (all ones). A circle with 3 can't have a 4-cell arrow.
- If you already know some digits on the arrow, subtract them from the circle's value to narrow down what's left.
- Combine the sums with the classic elimination techniques of sudoku.
How it differs from regular sudoku
Compared to classic sudoku, Arrow Sudoku adds sum arithmetic tied to a circle, in the spirit of Killer Sudoku but with a different approach. If you enjoy variants with lines and marks, you'll also enjoy other sum-based variants.
