Play Code Breaker code-breaking game free in your browser. Guess the secret color code using logic. No download required.
The game generates a secret sequence of colored pegs, typically four positions from a set of six colors, with colors repeating allowed. Make a guess by arranging pegs in the same number of positions. After each guess, you receive feedback: a black peg for each peg that is the correct color in the correct position, and a white peg for each peg that is the correct color in a wrong position. Use this feedback to narrow down the hidden sequence within the allowed number of guesses.
The most effective approach is systematic. Your first guess should contain distinct colors with no repeats, covering as many different colors as possible in one attempt. After receiving feedback, eliminate all color-position combinations that are inconsistent with the clues received. On subsequent guesses, choose an attempt that maximizes the information you expect to receive regardless of what the answer turns out to be. With disciplined elimination, most four-peg codes are solvable within five guesses.
Code Breaker was created by Israeli postmaster and telecommunications expert Mordecai Meirowitz and released by Invicta Plastics in the United Kingdom in 1971. It appeared in North American toy stores shortly afterward and became one of the most recognizable two-player games of the 1970s. The game prompted significant academic interest, with mathematicians and computer scientists publishing papers on optimal solving strategies. A version requiring five guesses or fewer for any four-peg, six-color game was proven possible, matching Meirowitz's original claim.