Transformer
by Tuomo Väliaho
It is almost standard to use transfers after one- or two-notrump openings. However, when opener rebids one notrump, transfers are seldom used. For example Bridge World Standard utilizes a form of XYZ, where responder's two-club bid is puppet to two diamonds used to show invitational strength and two diamonds is a game-forcing ask.
There are several reasons that make transfers desirable after opener's one-notrump rebid. Transfers create greater variety of bidding sequences and give responder more ways to describe his hand. Furthermore, according to The Balanced-Hand Principle (December 1989 Bridge World), it is better that unbalanced hands are described to the balanced ones, whose holders are better placed to judge how well the hands mesh. There is also a matter of concealment: asking-bids such as New Minor Forcing and XYZ reveal information about opener's pattern and help the defenders, especially when the final contract is three notrump.
Transformer is a method that combines a two-club puppet with transfers. The design goal is to keep invitations as low as possible: for example, responder is able to bid six-card major with invitational strength at the two-level. Responder is also able to show efficiently 5-5 and 6-4 patterns, and there are various ways to force to game with one-suiters and to announce a seven-card suit, a self-sufficient suit, and side shortness (even a void).
Using Transformer also has disadvantages apart from added complexity: in particular, responder cannot sign off in clubs at any level with a major and longer clubs.
Responder bids after one of a minor -- one heart -- one notrump:
Two clubs: puppet to two diamonds with (a) signoff in diamonds; (b) invitational-plus strength with exactly five hearts; (c) a balanced or three-suiter hand that is too strong to bid three notrump; or (d) support for opener's minor with game-forcing strength. Responder bids after two diamonds:
...Pass: signoff in diamonds...Two hearts: five-card heart suit; invitational strength
...Two spades: bidding the unbid major shows five cards in the original major; either a slam-try or desire to investigate the right game contract
...Two notrump: strong balanced hand or three-suiter; asks opener to describe further
...Three of a minor: support for opener's suit; game-forcing strength
...Three of an unbid minor: 5-5 in hearts and the bid minor; game-force
...Three hearts: five hearts, choice of games; asks opener always to bid four hearts with three-card support
...Three notrump: choice of games with five hearts and 5-3-3-2
Two diamonds: either a signoff in hearts or a six-plus-card heart suit with game-forcing strength. Opener bids two hearts, after which:
...Pass: signoff
...New suit: natural, 6-4
...Two notrump: one-suiter, good suit
...Three hearts: one-suiter, self-sufficient suit without shortness
...Three notrump: choice of games; weakish six-card heart suit and the unbid suits well-stopped
...Jump in a new suit: autosplinter; slam-try with self-sufficient one-suiter and short side suit
Two hearts: six-card heart suit; invitational
Two spades: 4-4 in the majors; invitational-plus strength
Two notrump: natural invitation
Three of a minor: support for opener's minor; invitational
Three of an unbid minor: 5-5 in hearts and the bid minor; invitational
Three hearts: seven hearts; slam-try
Three spades: self-sufficient six-plus-card heart suit and a spade void
Three notrump: Final contract
Four clubs|diamonds: self-sufficient hearts, club|diamond void
After one-of-a-minor opening, one-spade response and opener's one notrump, responder's bids are analogous to those after a one-heart response, except that two diamonds is a transfer to hearts (5=4 or 5=5 in the majors) with a game-force.
Responder bids after one club--one diamond--one notrump:
Two clubs: puppet to two diamonds [After opener's two diamonds responder passes or bids naturally four-card major at the two level to invite to game. Responder's two notrump is strong, and three clubs forces to game with club support. Three diamonds asks for major-suit stoppers, and a jump to three hearts|spades shows both minors and shortness in the bid major.]
Two diamonds: six diamonds; invitational strength
Two hearts/spades: natural with a four-card major; game-force
Two notrump: natural invitation
Three clubs: club support; invitational strength
Three diamonds: six-plus diamonds; game-force without a short major
Three hearts|spades: autosplinter with diamond one-suiter; game-force
Three notrump: final contract
Four clubs: autosplinter
The same technique can be used if opener's rebid at the one-level is in a major instead of one notrump. There are some exceptions in continuations: With extras, opener must bid above two diamonds after responder's two-club bid (which becomes a marionette). Responder's double jumps are splinters agreeing opener's second suit. Responder has a wide variety of ways to show support for opener's second-bid suit.
After one of a minor--one heart--one spade responder bids:
Two clubs: marionette to two diamonds, then:
...Pass: signoff in diamonds
...Two hearts: five hearts; invitational strength
...Two spades: four spades, invitational strength
...Two notrump: strong relay; asks opener to describe further
...Three of a minor: support for opener's original suit; game-forcing strength
...Three of an unbid minor: 5-5 in hearts and the bid minor; game-force
...Three hearts: five hearts; game-force without stopper in the fourth suit
...Three spades: spade support; slam try with 4=5=2=2
...Three notrump: choice of games with five hearts and the unbid suit stopped
...Four clubs|diamonds: spade support, five hearts and short clubs|diamonds
Two diamonds: either a signoff in hearts or six hearts with game-forcing strength. Opener bids two hearts, after which:
...Pass: signoff
...Two spades: at least 4=6 in the majors
...New suit: natural; 6-4
...Two notrump: one-suiter; good suit
...Three hearts: one-suiter; self-sufficient suit
...Three notrump: choice of games with a one-suiter; weakish heart suit and the unbid suits well-stopped
...Jump in a new suit: at least 4=6 in the majors; void splinter
Two hearts: six hearts; invitational strength
Two spades: spade raise, less than invitational strength
Two notrump: natural invitation
Three of a minor: support for opener's minor; invitational
Three of an unbid minor: 5-5 in hearts and the bid minor; invitational
Three hearts: seven hearts; slam-try
Three spades: 4-4 in the majors; balanced hand; slam-try
Three notrump: final contract
Four clubs|diamonds: splinter; 4=4=4=1 or 4=4=1=4
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