Bridges: Hashi — the Japanese archipelago puzzle
The puzzle from Tokyo
Bridges (also known as Hashiwokakero, "build bridges") is a Japanese logic game with two lines of rules and hours of depth. In front of you is an archipelago: circle-islands with numbers. The goal — connect them with bridges into one network.
Three rules
1. The number on an island — how many bridges must meet there.
2. Bridges never cross and run only in straight lines between neighbouring islands vertically or horizontally.
3. At most two bridges between two islands, and the whole network must be connected: from any island you can reach any other.
How to think
Start with the extremes. An eight is satisfied by eight bridges — no ambiguity there. A three in a corner or at the edge often has only one option as well. Then elimination kicks in: if a bridge is definitely somewhere, it is definitely forbidden somewhere else.
Our version is friendly from the first click: click the water between islands to place a bridge — one, two, click again to remove. Made a mistake? No problem, the board tolerates experiments.
Why it hooks you
Like Sudoku, Hashi has a magic property: the moment when chaotic circles suddenly fold into a single network always comes. An 8×8 board takes about five minutes, 11×11 — fifteen. A perfect dose of logic for an evening.