How to play

The Vault is a daily code-breaking game. One vault opens for the whole world each day, locked with a five-symbol code, and you get six attempts to crack it. It looks like Mastermind and it partly is — but a vault code is never random. It is always a meaningful ordered sequence, which means there are two ways in: grind the logic, or see the idea. The best players do both.

The rules

• The code is five symbols long, arranged in one specific order.
• You pick from a keyboard of ten symbols (eight on vaults before #15). Five of them are in the code; the rest are decoys.
• No symbol repeats. Every symbol in the code appears exactly once. This is the single most useful rule in the game.
• You get six attempts. Each one must be a full five-symbol guess.
• One vault per day, one attempt at it. There is no replay and no hard mode.

Reading the feedback

After each guess every slot comes back in one of three colours:

The counting trick

Because no symbol repeats, every guess of five distinct symbols is also a membership test on those five. Add your greens and ambers together and you know exactly how many of the symbols you just tried are in the code — regardless of where they sit.

On a ten-key board that is powerful. Guess five symbols and count: if you get three non-grey, then three of those five belong and two don't — which also means two of the five you didn'ttry are in the code. Your second guess can test the other five and, between the two, you often know the entire membership set before attempt three. At that point the puzzle stops being “which symbols?” and becomes “what order?”.

Then stop deducing and start reading

Once you know the five symbols, brute force is a bad idea: five symbols can be arranged 120 ways and you have three guesses left. But you never need to search, because the order is never arbitrary. Look at the five and ask what one sentence explains their sequence.

Past vaults have been ordered by moon phase, by time of day, by a chicken's life cycle, by the visible spectrum, and — once — by a rebus where pie equals π equals 3.14. The rule the designers hold themselves to is that the order must be defensible in a single sentence, and recognisable by a twelve-year-old once it's pointed out. If your explanation needs a paragraph, it's the wrong explanation.

This is why a good player can beat par badly. Par is what deduction alone costs. Seeing the pattern skips straight to the answer.

Why the decoys are hard

The five symbols that aren't in the code are not filler. They're chosen so you would plausibly place them: a decoy that you dismiss in a second has done nothing except make the keyboard look bigger. The genuinely nasty ones are contested substitutes — a symbol that fits a specific slot in your reading of the pattern just as well as the real answer does.

There is a fairness line, though, and it is strict: no decoy may create a second, equally valid answer. A decoy can make you hesitate. It can never make you right in a way the game refuses to accept. If two readings genuinely both work, that's a design bug, not a hard day.

What par means

Every vault ships with a par, and it isn't a vibe. A deterministic solver plays the exact code on the exact keyboard you get, never guessing anything inconsistent with the feedback it has already seen, and par is the number of attempts it needs. Typical par is about four on a ten-key board and about 3.6 on an eight-key one, and it is capped at five — a par-six day would need all six attempts from a perfect solver, leaving a human no margin at all, so those days get re-shuffled before they ever ship.

Beating par means you found something the solver couldn't: the idea.

A worked opening

Suppose the keyboard is ten symbols and you open with the first five. You get one green, one amber, three grey.

• Three symbols are gone forever. The keyboard is now seven.
• Two of your five belong — and you know one of their exact positions.
• Three of the remaining five symbols must be in the code, because the code needs five and you've only confirmed two.

Guess two now tests the other five while keeping your green where it is. After that you typically know all five members, and the last three attempts are for the ordering — which is where reading the pattern collapses the whole thing to one move.

Heists and treasures

Monday to Sunday forms a themed heist. Each day you crack yields one treasure, and the seven form a set with the crown piece on Sunday. Complete the set in its own week and it seals into your museum; miss a day and that slot stays a silhouette permanently, because there is no catch-up. Every treasure carries a true story — browse the museum or read back through the archive to see how past vaults worked.

No account, no catch

There is nothing to sign up for. Your streak, statistics and collection live in your own browser's storage, on the device you play on — which does mean that clearing your browser data clears your museum too, and that your progress doesn't follow you to a second device. That trade is deliberate: no accounts means no email, no password, and nothing of yours on our servers.