Bulls & Cows

About Bulls & Cows

Bulls and Cows is a classic code-breaking game that predates the boxed game Mastermind by decades. The computer picks a secret 4-digit code in which every digit is different. After each guess you get two clues: the number of bulls (a correct digit in the correct position) and cows (a correct digit in the wrong position). Use those clues to reason your way to the exact code — and try to do it in as few guesses as possible.

How the clues work

• 4 bulls means you've cracked it — every digit is right and in place.
• A cow tells you a digit belongs to the code, just somewhere else.
• Zero bulls and zero cows means none of those four digits are in the code — a very useful clue.