Bridges Solver (Hashi)

Bridges Solver — Step by Step

Click a square and type 1–8 to place an island with that number (⌫ removes it), then press Solve. Or play a generated puzzle and send it here with one click.

Bridges Solver: rules, how to use it, tips

Join the islands with straight bridges so each island has as many bridges as its number, nothing crosses, and every island is connected.

The rules

Each circle is an island with a number from 1 to 8.
Draw bridges between islands in straight lines, across or down. A bridge may not cross another bridge or pass over an island.
Two islands may be joined by one bridge or two (in the simpler version, only one).
Each island must have exactly as many bridges as its number, and all the islands must be connected into one group.

Using the solver

Choose the size and whether up to two bridges or one may join a pair, then click each island’s square and type its number (or press Sample).
Press Solve and step through: islands that need every possible bridge, ‘at least one’ deductions, full islands, and bridges that would cut a group off.

Tips

Count the neighbours. An 8 has four neighbours and needs two bridges to every one. A 6 in a corner-like spot with three neighbours needs two to each.
At least one each. A 5 with three neighbours can get at most 4 from any two of them, so it needs at least one bridge to the third — and in fact at least one to each.
Ones and twos. Two 1s can never be joined to each other, and a double bridge between two 2s would trap them: both pairs would be cut off from everything else.
Full islands. As soon as an island has all its bridges, its remaining directions are closed — which often forces its neighbours.

The full guide, with a worked example and common mistakes: How to play Bridges.

Questions

Can bridges go diagonally?

No — only straight across or straight down.

Do all islands have to be connected?

Yes. When the puzzle is finished you can travel from any island to any other along the bridges.

What is the one-bridge version?

A simpler variant for younger players where two islands share at most one bridge. Numbers are then never bigger than 4.

How do I solve a puzzle from a book?

Open the Bridges Solver, place each island and its number, and press Solve to step through every deduction.