Tresorknacker is a puzzle game that is meant for a large group of players (up to 40). Several groups of players compete to break into a safe by figuring out a six digit combination within a limited amount of time. In addition to mathematical and logical skills, the teams require a good deal of memory, co-operation and economy, as clues can be bought from the game moderator at varying prices of "time money". If several teams manage to break the code within the time limit, the team with the highest sum of "Time left" + "Time Money left" is the winner. As the code changes from game to game, several rounds can be played with the same group of players. No 21 in Christwart Conrad's "Taktisches Großgruppenspiel" series.