Numbun

Numbun is a number guessing game in a tradition known around the world as Bulls and Cows, Hit and Blow, 1A2B or Number Baseball, and close to Mastermind with digits instead of pegs. The secret number has unique digits and cannot start with 0. After each guess you get + for every digit in the right place and - for every digit that is in the number but somewhere else; a 0 means nothing matched.

There are two daily challenges, both the same date-based puzzle for every player. The Daily Puzzle is a four-digit number with ten tries. The Daily Case starts with five guesses already made and scored, and you have three tries to deduce the answer from them. Each has a calendar going back to the first daily game, marking days you solved, lost or left in progress.

Outside the dailies there is free play from two to nine digits, a Blind Start mode where you enter several guesses before seeing any results, hints, a whiteboard for notes and statistics. The site is free and ad-free, works offline once installed, and is available in English, Spanish, German, Russian and Turkish.