Puzzle Royale
How to play Hashi
Bridge the islands into one network
Also known as Hashiwokakero, Bridges.
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Connect every island
Solve it by bridging every island so you can travel between any two of them, with every island’s number fully matched.
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Tap to bridge islands
Tap the space between two islands to add a bridge — again for a double bridge, once more to clear it. Bridges run straight, horizontally or vertically.
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Match every number
Each island's number is exactly how many bridges touch it. Bridges never cross an island or another bridge.
Play Hashi now
Solving tips
- Fully forced islands: an 8 anywhere, a 6 on an edge, or a 4 in a corner takes double bridges in every available direction.
- One short of full (7 in the middle, 5 on an edge, 3 in a corner): at least one bridge in every direction — draw those singles now.
- Never join two 1s to each other, and never double-bridge two 2s (unless they’re the whole puzzle) — you’d seal them off from the rest.
- Every bridge must leave a route to the whole network — if a move would strand a group of islands, it’s wrong.
- Start at the borders: edge and corner islands have fewer directions, so more of their bridges are forced.
Where Hashi comes from
- First appeared in Puzzle Communication Nikoli #31 in September 1990, with a prototype form in issue #28 the year before.
- Invented by a reader writing under the pen name "Lenin", inspired by molecular bond diagrams from chemistry — the working title meant "atomic bonding".
- Lost in translation: hashi means "bridge" (橋), but with different kanji it means "chopsticks" (箸) — the puzzle has genuinely been published abroad as "Chopsticks".
- Runs in The Times as "Hashi" and in France, Denmark, the Netherlands and Belgium as "Ai-Ki-Ai".
- NP-complete — proved via a reduction from finding Hamiltonian cycles in unit-distance graphs.
- It’s pure graph theory: islands are vertices, bridges are edges, and solving means building one connected multigraph.
Play it against a hundred other solvers
Puzzle Royale wraps Hashi and seven other logic puzzles in a battle
royale: a hundred solvers enter, four rounds, half the field goes out each time,
one champion. Or play it untimed in Practice with no stakes at all.
Try a Hashi puzzle
The other seven