Play hashi online, free and unlimited
A new bridges puzzle every time you press the button, in your browser: no sign-up, no ads, no timer. Every board has exactly one answer, so you can always finish it by logic.
Tap an island, then tap a neighbouring island in the same row or column: one bridge, tap again for two, again to remove. With the keyboard: Tab to an island, press Enter to pick it, then an arrow key toward a neighbour to add, double or remove a bridge. A filled island has all its bridges; a dashed outline means too many.
How this works, and what it does not do
Boards come from the same generator as the Causeway daily puzzle: a connected network of islands with extra loops, numbers written from the finished network, and each board kept only if a solver finds exactly one answer. "Check my bridges" tells you whether your bridges match that answer; it does not mark individual mistakes, so you keep the satisfaction of finding them. Never played? Read the five rules or the solving guide, and use the certain-bridges table when you are stuck. Stuck on a puzzle from somewhere else? Paste it into the solver.
Honest limits: this page checks uniqueness with one solver, where the daily puzzles are also checked by two more independently written counters. Progress is not saved if you reload. For a shared puzzle each day with a streak and a spoiler-free result card, try the daily (free; the optional $4 Supporter Pass adds an archive and practice sets).