It is used when the declarer has enough high cards to take all but one of the remaining tricks, but does not have enough communication between the hands to cash them.
It was analyzed and named by Terence Reese in the book "The Expert Game", also titled "Master Play in Contract Bridge".
The name stepping-stone alludes to South's use of West's ♥A to cross over to the abandoned ♠A.
This squeeze would work equally well with the East and West hands reversed.An interesting variation is the following ending playing in no trumps with the lead in South: NW ES Needing all but one of the remaining tricks, the declarer leads the ♠10 covered by West, dummy winning with the ♠A.
When the winning diamond is led from dummy (declarer throwing a heart) both defenders are subjected to a stepping-stone squeeze.