Evidence Locker

About the game

Evidence Locker is a free logic game in the tradition of classic code-breaking puzzles. Each locker is sealed with a secret code made of evidence symbols: a badge, a key, a fingerprint, handcuffs, a siren and a magnifying glass. You enter a guess, and the lock answers with clue lamps. Using those clues, you work out the code in as few guesses as possible.

There are 12 lockers. The first uses a three-symbol code from just four symbols. By the Chief's Vault, the code is five symbols long, all six symbols are in play and a symbol can appear more than once. A new secret code is chosen every time you start a locker, so you can replay any locker as often as you like.

How the clue lamps work

After every guess, a row of lamps lights up next to it, one lamp for each symbol in the code:

• Green lamp: one of your symbols is the right symbol in the right place.
• Yellow lamp: one of your symbols is in the code, but in a different place.
• Dark lamp: no match for one of the symbols.

The lamps are always sorted with green first, then yellow, so they do not tell you which of your symbols earned which lamp. Working that out is the puzzle. A symbol is only counted once: if the code has one key and you guess two keys, at most one of them lights a lamp.

An example

Say the secret code is Key – Badge – Siren and you guess Badge – Key – Siren. The siren is in the right place (one green lamp). The badge and the key are both in the code but swapped (two yellow lamps). Your next guess could simply swap the first two symbols, and the lock opens.

Stars and the par

• 3 stars: open the locker in the par number of guesses or fewer, without a hint.
• 2 stars: up to two guesses over par, or any solve that used the hint.
• 1 star: any other solve within the guess limit.

We set each par by simulating thousands of games played by a careful solver that only ever guesses codes which fit every clue so far. Such a solver beats the par in about 97–100% of games, so three stars are always within reach if you use every lamp. If you run out of guesses, the code is revealed and you can try a fresh code straight away.

The Hint button (once per locker) fixes one correct symbol in place. It is great when you are stuck, but it limits that attempt to two stars.

The twelve lockers

On "no repeats" lockers every symbol in the code is different, and the game will not let you place the same symbol twice. From Double Trouble onwards, the code may contain the same symbol two or more times.

Tips

• Every guess should fit every clue. Before you press Check, ask: "Could this be the code, given all the lamps so far?" If not, it wastes a guess.
• Dark rows are gold. A guess with no lamps at all rules out every symbol in it, everywhere.
• Change one thing at a time when you are close. Swapping just two symbols tells you exactly which one moved into place.
• On repeat lockers, try doubles early. A guess like Badge–Badge–Key–Key tells you quickly whether badges or keys appear, and how many.
• Count the lamps. Green plus yellow is the number of correct symbols, whatever their order. Once that total equals the code length, you only need to sort them.

Frequently asked questions