Bridges Solver
Solve a Bridges (Hashiwokakero) puzzle of islands and bridges.
Bridges, also called Hashiwokakero or Hashi, is a network puzzle. Each numbered island must be joined to its neighbours by that many straight bridges, running only across or down, with at most two bridges between any pair, no bridge crossing another, and every island linked into one connected network. Click a cell to cycle its island number from 1 to 8, then solve.
Click a cell to cycle its island number, or back to water.
How it works
The solver looks at each island's nearest neighbour across and down and decides 0, 1, or 2 bridges on every such link. It keeps each island on track for its number, refuses a bridge that would cross one already placed, and at the end checks that every island is reachable from every other.
A proper Bridges puzzle has one solution; the solver reports when more than one network fits.