Play Mastermind Here!
Or press the solve button to see the game won in 5 or less moves with Knuth's algorithm described here.
See my blog for a more thorough background and walkthrough of the code.
Guess the right sequence of colors. For each attempt, you will be scored with black or white pegs.
Black means right color, right position for one of the columns.
White means right color, wrong position for one of the columns.