The Daily Bridges Puzzle

Today’s board, at any size from 7×7 to 15×15. It is built from today’s date, which is why yours and everybody else’s are the same board.

Your record

• —Current streak
• —Longest streak
• —Days played
• —Best time, this size

A daily with nothing behind it

There is no server here to hold a puzzle of the day and hand it out, so the date does the job instead. The calendar day becomes a number, the number drives every choice the network builder makes, and the same number therefore grows the same islands and the same bridges on any machine running this code — with no coordination and no request.

Bridges makes that arrangement work harder than the binary puzzle does. A binary grid is carved from a finished solution, so the generator knows in advance roughly what it will get. A network cannot be carved: it is grown, the numbers are read off it, and only then is it judged. Boards that turn out to need a guess, or to have a second answer, are discarded and another is grown. All of that happens on your machine, in a worker thread, in a few milliseconds — but it does mean today’s board is genuinely the twelfth one your browser built and the first eleven were thrown away.

Because it is a function of the date and nothing else, every board is reconstructible forever. A link to a Tuesday in April opens the exact islands people were joining that Tuesday, five years from now, on a computer that has never contacted this site.

The bridges week is not the binary week

Difficulty follows the weekday, read in UTC so everybody turns the page at the same moment. Sunday and Friday are the demanding ones here, Monday and Wednesday the gentle ones, and Saturday is the board that leans hardest on the connectivity argument.

That shape was chosen against the other puzzle’s rather than copied from it. Somebody who plays both should meet one board they can finish and one to grow into on most mornings; two peaks on the same day and two easy boards on the same day would waste half the week. It is the one piece of editorial coordination between the two sections and it is worth the small amount of bookkeeping.

Size is an independent choice and does not touch difficulty. A 15×15 easy board is a long sit rather than a hard one — the same two observations, made thirty more times. Choose the size for the time you have and the day for how much you want to be made to think.

The streak, the clock and what a hint costs

Finishing any one size records the day. Playing all five does not record five, there is no table to climb, and the number is only a record of having turned up — which is the only honest thing a daily can measure about anybody.

The hint names the argument it used and links to the page that explains it, so taking one is the site working rather than a failure. It does not break a streak and it is not hidden in the share text either: the result you copy says how many you took, because a time set with four hints and a time set with none are different results and quietly conflating them would make the whole thing pointless.

The clock can be turned off entirely if it is the sort of thing that spoils the puzzle for you, and the setting sticks. Everything — streak, history, best time per size — lives in this browser’s local storage, is never transmitted, and disappears for good if you clear site data for this domain.

Common questions

More Bridges pages

• Hashi puzzleUnlimited boards
• Bridges rulesFive rules, in full
• Solving a boardA 9×9, worked
• Bridge techniquesThe whole ladder
• Island countingTechnique — easy
• CrossingsTechnique — medium
• Spare capacityTechnique — hard
• IsolationTechnique — expert
• Guessing at bridgesTechnique — refused, here too
• Printable bridgesFor paper
• Bridges archiveEvery past board