Players in collusion with one another have massive advantages over any non-colluding player(s). The basic strategy of colluding players is to preserve the high "control" cards against the non-colluder(s), and not to waste these cards amongst themselves. This strategy is called "holding" or "warrening". Other collusive techniques include signaling (through the played cards, e.g. odd/even as in bridge, or non-verbal cues) where the strength of the hand, number of controls, hand type, exact high cards, and other features of the hands are transmitted to the partner.