pass after doublePartial support for partner's suit, e.g. three after 1S 2D, or a doubleton after 1S 2H.
redoubleNot even partial support for partner's suit, either a singleton or doubleton. However not a void, because partner might gamble to play in the redoubled contract. Says nothing about strength, since the partnership is known to have at least game-going values.
Rebidnatural, denies trump support
Raisetrump fit.
Jump shiftnatural, game-forcing
Jump raiseTrump fit, reversing strength. If four of a minor, Minorwood.
Jump rebidBig six-card suit, reversing strength.
New suitNatural (even if the opposition have overcalled in the suit), 5-4 shape, denies trump support
Unnecessary jump shift up to Splinter LevelSplinter, agreeing partner's trump suit and showing a small singleton or void. Splinters are normally game-forcing, but if two of them were available then the lower is merely invitational, e.g. 1C 1S 3D/4D are both splinters, since 1C 1S 2D would have been a reverse.
Jump shift at splinter levelsplinter
2NT12-14 balanced, no support for partner's suit
Game-level rebidGood 7-card suit (missing at most one of the top four honours) that would be (a) happy in game opposite a void and (b) good for grand slam opposite that missing singleton honour. However the hand's nothing special in terms of high cards, probably 12-14 points or so.
3NTto play, if jump then a void in partner's suit
4NTBlackwood, for responder's suit if major
Jump raise to 54-card support for partner in an unbalanced hand, but without any key cards or small singletons.
5-level rebidCompletely solid trump suit, no losers even opposite a void. Responder's next bid is RKC Blackwood response, showing Key Cards.
Jump shift to Blackwood LevelExclusion Blackwood
Jump shift to Grand-Hunting LevelComplete two-suiter. If the partnership had previously bid more than one suit and so there's ambiguity about which suits are being promised, then the other one is the first-bid suit of the player who just jumped.
Any slamNo systemic agreement; the natural interpretation
Copyright 2015 Finn Clark.