Sudoku and Hashiwokakero are both grid-based logic puzzles you solve by pure deduction, so solvers naturally wonder how alike they really are. The short answer: Hashiwokakero is distant to Sudoku. Below we lay out what the two share, where they part ways, and whether the skills you have built on Sudoku will carry over.
- Grid: Islands on a grid
- Closeness to Sudoku: Distant
- Also called: Bridges, Hashi, Chopsticks
What is Hashiwokakero?
Join numbered islands with bridges so each island has exactly its number of bridges and everything is connected. Here are the rules in full:
- Draw straight horizontal or vertical bridges between islands; a number is that island's total bridge count.
- At most two bridges join any pair, and bridges never cross.
- Every island must end up connected into one network.
What a Hashiwokakero looks like
Hashiwokakero joins numbered islands with bridges — the number is that island's total bridge count, at most two per pair, none crossing, all connected. Here is a small solved network of three islands.
Three islands joined: a double bridge (top) and a single bridge (right) — 2, 3 and 1 bridges.
It is a single-solution deduction puzzle, and "this island needs two bridges and has one neighbour, so both go there" is the same forced-count reasoning behind a Sudoku hidden single. But you connect islands with bridges rather than fill a grid of digits — a distant relative.
What Hashiwokakero shares with Sudoku
- It is a single-solution deduction puzzle with no guessing needed.
- Both are solved by spotting where a count forces a unique arrangement.
How Hashiwokakero differs from Sudoku
- You connect islands with bridges; there is no grid of digits to fill.
- The numbers are connection counts, unrelated to Sudoku's 1–9.
Do Sudoku skills transfer?
No Sudoku technique applies, but "this island needs four bridges and has only two neighbours, so both must be doubled" is exactly the forced-count reasoning behind a Sudoku hidden single.
The verdict
Bridges shares Sudoku's forced-deduction feel but plays out as a network-building puzzle, not a filling one.