Hashi (Bridges)Free, no sign-up

(1) The number on an island is how many bridges connect to it. (2) Bridges run straight, horizontally or vertically, to the next island. (3) At most two bridges may join the same two islands. (4) Bridges may not cross each other. (5) In the end, all islands must be connected into one group. That's all five rules.

Yes. Hashiwokakero ("build bridges!") is the name used by the Japanese puzzle magazine Nikoli, and the puzzle is also known as Hashi and Bridges. The rules are identical.

Each tap (or click) between two islands cycles the bridges 0 → 1 → 2 → 0. You can't build where it would cross another bridge. On a keyboard, press Tab to choose a bridge position and Enter or Space to cycle it.

Yes. Every puzzle is built to have a unique solution. You can solve it with logic alone, such as "an 8 has two bridges in all four directions" or "joining two 1s would cut them off from the rest".

By the time from opening the puzzle to solving it, fastest first. You only need a nickname, and you can submit up to 30 times a day per size. The server checks that your board follows the rules.