How to play Hashi (Bridges): a complete beginner's guide
• ~5 min read
Hashi — full name Hashiwokakero, Japanese for "build bridges" — is a logic puzzle in the same family as Sudoku. It's pure deduction, no guessing, and a whole solve fits in five to ten minutes. Here's everything you need to start.
The rules (90 seconds)
You're given a board of circles ("islands"), each with a number from 1 to 8 inside. Your job: draw bridges between them. The rules:
1. Match the number
The number on an island = the total bridges connecting to it. An "8" needs eight.
2. Straight lines only
Bridges go horizontally or vertically. No diagonals.
3. Max two between any pair
You can have one or two bridges between the same pair of islands. Never three.
That last rule is what makes Hashi hard. You can satisfy every island's number perfectly and still lose — because you've accidentally split the board into two separate sub-networks. Always sanity-check connectivity before you finish.
The four techniques you actually need
1. Max-out the corners
A corner island has at most two neighbours. If it shows a 4, both neighbours must have double bridges — there's literally no other way to make four. Same logic for edges with 6 or 7.
2. The "one less than max" trick
If an island has N neighbours and shows 2N − 1, you can place one single bridge to
every neighbour for free — because at least one bridge must exist on each connection. Same for
edge-touching 5s with three neighbours: at least one bridge each.
3. Mark forbidden directions
When you can rule out a direction (because a perpendicular bridge already crosses it, for example), mentally mark it. The remaining bridge count then has fewer ways to be made — often only one.
4. The isolation check
Before connecting two clusters in the final move: imagine the puzzle without that bridge. Are the clusters still going to merge somewhere else? If yes, you're safe. If no, that bridge is forced.
The three beginner mistakes
- Filling islands greedily. You see an "8" and immediately reach for double bridges on all four sides. Often correct! But if one of those neighbours is a "1", you've broken the puzzle. Always check the neighbour's number first.
- Ignoring connectivity until the end. A pair of two-island loops that satisfy every number is still wrong. Build outward from a central cluster.
- Guessing. Hashi never requires a guess. If you feel stuck, you've missed a constraint — usually a "no perpendicular crossings" implication.
Where to play
Our daily HashiGlyph runs three board sizes (7×7, 9×9, 11×11) and a built-in connectivity-check toggle so you can spot the "two separate networks" mistake before submitting. No ads in the grid, no signup, free.