Connect numbered islands using one or two bridges at a time until all counts match and the map forms a single network.
Bridges Island Puzzle is a logic game set on a grid of round islands, each marked with a number. You draw bridges between them, and that number tells you how many bridges must end at the island. You finish once all the counts are satisfied and you can travel from any island to any other.
There is no guessing involved. Each board is checked by a solver before you see it, so a clean chain of reasoning always leads to the answer.
Rules in brief
- Bridges are straight and run only horizontally or vertically.
- Bridges may never cross one another.
- Two islands can share one bridge or a pair of parallel bridges, but no more by default.
- A double bridge counts as two for both of its islands.
- Every island must connect, directly or through others, to every other island.
Getting started
Drag from an island toward a neighbor to build a bridge. Drag the same way again for a double, and once more to remove it. Right-drag, or press and hold on a touch screen, to mark that two islands will never be linked. A plain click or tap locks an island as finished, which highlights it and protects its bridges from stray drags.
The Type menu offers maps of 7x7, 10x10 and 15x15 at easy, medium or hard. Custom settings let you change the size, how crowded the islands are, the maximum bridges per direction from one to four, and whether loops are permitted.
Winning moves
Begin where choices are fewest. A corner island marked 4 has only two possible neighbors, so it needs a double bridge to each. In the same way, an island showing 6 with just three neighbors must send two bridges to all of them.
Watch out for closing off small groups. Linking two 1s to each other seals them away from the map, and so does joining two 2s with a double bridge. Unless those are the only islands, that move can never be right.
Good to know
Mistakes that are certain turn red right away. An island goes red when it has too many bridges, when it can no longer reach its number, or when its group has been sealed off from the rest. Catching those early stops one slip from spreading. Number keys jump the keyboard cursor to an island with that value.
Controls
| Action | Keyboard | Mouse | Touch |
|---|---|---|---|
| Build a bridge (repeat for a double, again to remove) | Ctrl + arrow, or Enter then an arrow | Drag from an island toward its neighbor | Drag from an island toward its neighbor |
| Mark two islands as not linked | Shift + arrow | Right-drag between islands | Press and hold an island, then drag |
| Mark an island as finished | Space, or Enter twice | Left-click the island | Tap the island |
| Jump to an island with a given number / show possible links | Number keys / G | — | — |
| New game, undo, redo | N, U, R | Menu buttons above the map | Menu buttons above the map |
Bridges Island Puzzle FAQ
Can I play Bridges Island Puzzle on a phone or Chromebook?
Yes. On a touch screen, a short flick from an island toward its neighbor builds a bridge, so small screens are fine. On a Chromebook you can drag with the trackpad or play entirely from the keyboard, using arrows with Ctrl or Shift.
How long does one puzzle take?
It depends on the map you choose. A 7x7 easy map can go quickly, while a 15x15 hard map is a much longer think. Pick the size and difficulty from the Type menu to match the time you have.
What should I do when I get stuck?
Press G. Gray lines appear for every connection that is still possible, which makes it easy to see which islands have run out of options. Undo with U also lets you step back to the last spot you were sure about.
What is the win condition?
Every island must have exactly the number of bridges it shows, no bridges may cross, and all islands must link into a single group. When all three are true, the map flashes to tell you it is solved.
