For adults learning Hashi bridges puzzles: tell us where you get stuck, get the one technique that fixes it.
Where do you get stuck?
Tap the one that sounds like you. Each answer is a technique you can test on the 9-island board below.
By the Honest Little Apps studio · Updated November 2026 · We make Sumbriska, a sum-based bridge puzzle; these tips are for classic Hashi.
The short answer
Solve a bridges puzzle by placing only bridges you can prove. Start with islands that have one neighbor or whose number is twice their neighbor count, then treat full islands as walls and recount. Finish by checking that every island joins one network. Never guess; every fair Hashi has a logical next step.
The rules, as Nikoli, the Japanese publisher that named the puzzle, lists them:
Every bridge you draw should come with a reason you could say out loud.
Try it
Tap the dotted line between two islands to add a bridge; tap again for a double, once more to clear it. Islands turn green when full. Stuck? Press Next step and the board places one proven bridge and tells you why.
Start with the corner 2 at the top left. How many neighbors can it see?
We generated this board and checked by computer that it has exactly one solution.
Cheat sheet
One rule covers most openings: an island showing n with k neighbors must send at least n − 2(k − 1) bridges to every neighbor.
| Island | Neighbors | Forced |
|---|---|---|
| 1 or 2 | 1 | All bridges to it |
| 3 | 2 | 1 each way |
| 4 | 2 | 2 each way |
| 5 | 3 | 1 each way |
| 6 | 3 | 2 each way |
| 7 | 4 | 1 each way |
| 8 | 4 | 2 each way |
CORNER 4EDGE 6ANY 8
Those three are full the moment you see them. The Wikipedia summary of Hashi techniques lists the same corner, edge and interior patterns.
Be honest
Method
Most mid-board jams end the moment you count a full island as a wall.
Same habits, new bridge
In Sumbriska each island shows a target number, and every bridge carries two numbers, one for each end. Flipping a bridge changes both islands' totals, and you win when every sum lands exactly. Counting, treating finished islands as walls and refusing to guess carry over directly.
One design decision we stand by: hints, Undo and step explanations are always there and never cost XP, because the point is learning the logic. The honest limit: the free download includes regions 1 and 2, the Daily board, The Deep and Harbor Run; regions 3 to 6 and the side boards need the optional Voyage Pass ($4.99 a month or $29.99 a year, no free trial).
Side by side
Count bridges: an island's number is how many bridges touch it.
Balance sums: each flip sends numbers to both ends of a bridge.
Hard part: crossings and keeping one connected network.
Hard part: one flip moves two totals; Two Tides boards must solve twice.
Like counting? Stay classic. Like arithmetic and a harbor that grows as you solve? Try Sumbriska tonight.
A quiet, clever number puzzle with a Daily board, no ads, no accounts, and full offline play. Try it tonight.