Bridges Puzzle

How to play the bridges puzzle online

1. Above the board, pick a Size (7×7, 9×9, 11×11, 13×13 or 15×15; the default is 9×9) and a Difficulty (Easy, Medium or Hard). Select New puzzle. Wait for “Generating…” to finish if it appears.
2. To add a bridge, drag from an island toward a neighbouring island in its row or column.
3. Drag again to make a double bridge, and a third time to remove it. You can also tap an existing bridge to cycle it through the same steps.
4. To erase a bridge, right-click with a mouse or use the Erase chip. On a phone or tablet, the Bridge and Erase chips above the board choose what a tap does.
5. Watch the islands. An island turns grey when it has its number of bridges. If “Show rule errors as I play” is on, rule breaks appear in red straight away.
6. Use Hint when you are stuck, Check to compare your board with the rules and solution, and Undo or Redo to step back and forward.
7. When the puzzle is solved, the page shows “Solved in m:ss” and how many hints you used. Select Next puzzle to continue.

Arrow keys move the cursor. W, A, S and D add a bridge from the island under the cursor up, left, down or right, and Backspace clears its bridges. Restart clears the board but keeps the same puzzle. Copy link gives you a link that opens exactly the same puzzle, and Print prints it.

Bridges puzzle rules

A Bridges puzzle is solved when every island has the number of bridges shown on it and all islands form one connected group. The rules are short, but they decide every move you make.

Each island is a circle with a number from 1 to 8. Bridges run straight, horizontally or vertically, and each island’s number is how many bridges end on it. At most two bridges can join the same pair of islands. Bridges never cross each other, and they never pass over an island. Finally, all islands must be connected into a single group.

The name hashiwokakero is Japanese and means “build bridges”. It is a Nikoli puzzle.

How to solve hashi

Solve hashi by making deductions that the rules force, one step at a time, and start with the easiest ones. Easy puzzles can be finished with four basic rules, while Medium adds three more techniques. Hard puzzles also need trial, where you assume a bridge count and follow it until it breaks a rule.

The basic rules are:

• Complete: an island that already has all its bridges takes no more.
• Maxed: when an island needs exactly as many bridges as its open sides can still take, each open side gets its maximum. An 8 always has double bridges in all four directions. A 6 with three neighbours, a 4 with two neighbours and a 2 with one neighbour are full too.
• Limit: a pair of islands can get no more bridges than either end still needs. So a 1 never gets a double bridge.
• Crossed: a side blocked by a crossing bridge stays empty.

The Medium techniques are:

• Min: when an island needs more bridges than its other sides can take, the remaining side needs at least the difference. A 3 with two neighbours needs at least one bridge to each, and a 7 needs a bridge in every direction.
• Isolate: a bridge that would close off a finished group while other islands are still outside is impossible. Two 1s never join each other, and two 2s get at most one bridge between them.
• Exit: a group that is not finished, with only one way left to reach the others, must use that way.

A small example from the 7×7 Easy generator shows the maxed rule at work. A 2 in a corner with one neighbour takes a double bridge, because it has just enough room for the bridges it needs.

Frequently asked questions

Is the Bridges puzzle free, and do I need an account?

Yes, it is free, and there is no account or sign-up. Progress and settings are saved automatically in your browser and restored when you come back. Nothing is uploaded.

Can I play the Bridges puzzle on a phone?

Yes. It works on phones, tablets and computers. On a touch screen, the Bridge and Erase chips choose what a tap does, and Move lets you scroll a zoomed board.

Can I print the Bridges puzzle?

Yes. Select Print to print the puzzle on its own page, with its size, difficulty and rules. Tick “Print the answer page too” to add the solution on a second page. In the print dialog you can choose “Save as PDF”. A4 and Letter paper both work.

Does every Bridges puzzle have only one solution?

Yes. Each puzzle is generated from a random seed and kept only when the site’s solver proves it has exactly one solution. That means you can always finish it by logic, without guessing between two answers.

What does hashiwokakero mean?

Hashiwokakero is the Japanese name for the puzzle, and it means “build bridges”. Hashi is its short form, and the puzzle is also called the Bridges puzzle or bridges game.

Can I use bridges (hashi) puzzles from here commercially?

Yes. Bridges puzzles from this page are royalty-free for personal, classroom and commercial use, including KDP puzzle books, Etsy and Teachers Pay Teachers listings, and print-on-demand products. No credit is required. The only thing you may not do is copy the generator or the site itself to run a competing service; see the terms.

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