This is a squeeze play, in which both of the opponents
are squeezed in the trump suit. The discovery of this particular play technique is unknown as is the origin of the designation.
An illustration should clarify this concept.
Clubs are trump. South is the declarer and needs all six tricks to fulfill the contract. South plays the Jack of Clubs. West is forced to discard a small Heart and South discards the small Diamond from the dummy.
East is squeezed in all three suits. In the case that East discards a Spade, then South can finesse West in Spades. If East discards a Diamond, then the Jack of Diamonds becomes a winning trick. If East discards a Heart, then South will play to the Ace of Hearts in the dummy, ruff the 5 of Hearts with the last trump, cross to the dummy to play the 7 of Hearts.
If you wish to include this feature, or any other feature, of the game of bridge in your partnership agreement, then please make certain that the concept is understood by both partners. Be aware whether or not the feature is alertable or not and whether an announcement should or must be made. Check with the governing body and/or the bridge district and/or the bridge unit prior to the game to establish the guidelines applied. Please include the particular feature on your convention card in order that your opponents are also aware of this feature during the bidding process, since this information must be made known to them according to the Laws of Duplicate Contract Bridge. We do not always include the procedure regarding Alerts and/or Announcements, since these regulations are changed and revised during time by the governing body. It is our intention only to present the information as concisely and as accurately as possible.