Structure
In the ordinary compound squeeze, the squeezer holds one single threat and two double threats in a one-loser ending. As with the 1-loser triple squeeze, the play of the second last free winner squeezes the player with three stoppers, forcing that player to abandon one of the doubly-stopped suits, leaving a standard double squeeze after the squeezer cashes the remaining winners in the suit just abandoned. Two broad classes of compound squeeze are distinguished:
Unrestricted: Here the last free winner can be cashed before the squeezer must decide which threat was abandoned by the player with three stoppers. This can only happen if the lone threat is recessed (to provide a discard for one of the threats in the opposite hand).Restricted: Here the squeezer must immediately cash the remaining winners in the double threat which was abandoned by the player with three stoppers, before cashing the last free winner. Restricted endings are thus inherently more ambiguous.
Since either double threat may end up as the middle suit in a double squeeze, each double threat must have an entry. Also, the single threat must lie over the player with three stoppers (otherwise, that player can abandon a suit held to that player's left, leaving all three threats stopped from behind).
One unusual possibility in compound squeeze play is the alternating threat. A holding such as 4 3 opposite A 2 has a functional threat card in either hand; normally this flexibility is of no importance, but certain compound squeezes are able to exploit it.
Classification
Double squeezes were classified according to the nature of the lone threat (the threat in the hand which contains only one threat). Aside from the possibility of an alternating menace, the same scheme can be used for compound squeezes. This gives six classes of compound squeeze: