For each factor, so-called forcing values are calculated for the time period between 1750 and the present day.
The one-heart response guaranteed at least five hearts and game-forcing values.
One heart promised game-forcing values with at least five hearts.
North cue-bid two spades to say that he had game-forcing values.
Stansby (North) cue-bid three diamonds to show game-forcing values.
The North Wbridge5's raise to three hearts promised four-card support and at least game-forcing values.
And with game-forcing values North would cue-bid four clubs, which would make no statement about his club holding.
North's response of two no-trump was the Jacoby Forcing Raise, guaranteeing at least four-card spade support and game-forcing values.
Feldman's partner thought that his three-diamond rebid guaranteed game-forcing values and that with a weak hand, he would have rebid an artificial two no-trump.
Cohen (North) doubled to show game-forcing values but denying a good long suit or a balanced hand with spade stoppers.
The measured force values were read manually.
