The Doppit Almanac · No. 42

Spanit

Join every island into one network

What it is

Spanit is Hashiwokakero, better known in English as Bridges. The board is a scatter of numbered islands. You join them with bridges that run straight across or straight down, and the number on an island says exactly how many bridges have to reach it. Two islands can take one bridge or two, and never more.

Bridges never cross and never pass through an island, so a bridge you lay in one place rules out every line it blocks. The last rule catches people: when you are finished, every island has to be reachable from every other. A group that closes into its own little map is wrong, however well the numbers add up.

How it plays

• Join the islands with bridges until every island can be reached from every other.
• An island takes exactly its number of bridges.
• A bridge runs straight across or straight down from island to island, and two islands take one bridge or two.
• Bridges never cross each other and never pass through an island.
• On Expert some islands show a question mark instead of a number. A question mark takes any number of bridges, but at least one has to reach it.
• One lays a single bridge, Two lays two, None marks a line you have ruled out. Tap the faint line between two islands, or drag along it.
• An island greys out once it has its number. Stuck? Hint names the next forced bridge.

The difficulties

Easy is eight by eight with eleven islands, under a minute of counting what each can still reach. Medium is eleven by eleven with twenty two, where finishing one island quietly settles the next three. Hard is fourteen by fourteen and deliberately thin: more islands would make it easier, not harder, because high numbers settle a region on their own. Every hard board needs at least two stretches where you assume a count, follow it until it breaks, and take the other. Expert is twelve by twelve, smaller on purpose: the setter rubs the numbers off as many islands as the board can carry and still have one answer, so seven or eight show a question mark and you work their counts out from what is left. Those gaps stop the hard tier's move working alone, and every expert board needs at least one follow-through that takes a second assumption inside the first. A fresh board is dealt every day, for nothing.

Nearby in the almanac: Pipeit, Trackit and Fencit