Transfers

Transfers over a notrump opening shows length in the next suit and gives no information about strength. This puppet-like behavior saves bidding space. Wbridge5 implements French 4-way transfers, which involves only suit bids. This spares notrump bids for their natural meanings.

A major transfer shows 5+ cards. A minor transfer shows 6+ cards because a fit is needed to go over the next notrump.

Opener's rebids

1NT opener's rebids

An 1NT opener always accepts transfers because playing a 2-level suit contract with a 7-card fit is acceptable.

Opener may super-accept with 18+ points and 4+ cards to counter-invite responder.

Acceptances

1NT-2♦; 2♥

1NT-2♥; 2♠

1NT-2♠; 3♣

1NT-3♣; 3♦

Super acceptances, 18+ points, 4+ cards

1NT-2♦; 3♥

1NT-2♥; 3♠

1NT-2♠; 2NT

There is no super acceptance for diamonds due to lack of bidding space.

2NT opener's rebids

Opener may have a singleton with 4-4-4-1 pattern. As a result, a 2NT opener tries to reject a transfer with a singleton.

The Wbridge5 AI also tries to reject a transfer with a doubleton, but this mixes signletons and doubletons together. Responder already rebids notrump to show exactly 5 cards, so there is no need to reject a transfer with a doubleton. Rejection only with singleton helps responder make decisions.

Transfer to hearts 3♦

Transfer to hearts is always accepted to protect the auction 2NT-3♦; 3♥-3♠, which shows weak 5-5 majors.

3♥

Acceptance.

3♠!, 4♣!, 4♦!

Super acceptance, control bid, 22+ points, 4+ cards in hearts.

4♥!

Super acceptance, all suits controlled, 22+ points, 4+ cards.

Transfer to spades 3♥

Responder will show if there are 6+ cards in the next round, so rejection shall show a singleton to dissuade partner early.

3♠

Acceptance, 2+ cards.

3NT

Rejection, singleton in spades.

4♣!, 4♦!, 4♥!

Super acceptance, control bid, 22+ points, 4+ cards in spades.

4♠!

Super acceptance, all suits controlled, 22+ points, 4+ cards.

Transfer to clubs 3♠!

Rejection with doubleton makes sense because acceptance is a mediocre 4♣. There is no super acceptance because a normal acceptance already shows 3+ cards with which responder seldom passes.

3NT

Rejection, singleton or doubleton in clubs.

4♣

Acceptance, 3+ cards.

Transfer to diamonds 4♣!

Opener is forced to accept due to lack of bidding space.

4♦

Relay, forced acceptance.

5♦

Super acceptance, 23+ points, 3+ cards in diamonds.

Second responses to an 1NT opener

Opener always accepts transfer even with only 2-card support. Therefore, 6 cards are required for responder to assume a fit.

Transfer to hearts 2♦

Relay 2♥

The special 1NT-2♦; 2♥-2♠ auction shows a weak hand with 5+ cards in both majors.

2♠

0~8 points, 5+ spades

2NT

Invitational, exactly 5 cards in hearts.

3♣, 3♦

Forcing to game, 4+ cards.

3♥

Invitational, 6+ cards.

3NT

Forcing to game without slam interest, exactly 5 cards in hearts.

3♠!, 4♣!, 4♦!

Splinter, slam try (14+ points), 0~1 cards, 6+ cards in hearts.

4♥

Signoff, 6+ cards.

Super acceptance 3♥

Responder shall bid game with all former invitational hands because opener has shown maximum. Moreover, responder can upgrade some weak hands because of the 9-card fit.

Other bids are slam tries because a good major fit is already found.

3NT

Forcing to game, balanced.

3♠!, 4♣!, 4♦!

Slam try, control bid.

4♥

Signoff, strong enough to play.

Transfer to spades 2♥

Relay 2♠

The special 1NT-2♥; 2♠-3♥ auction shows a slam try with 5+ cards in both majors.

2NT

Invitational, exactly 5 cards in spades.

3♣, 3♦

Forcing to game, 4+ cards.

3♥

Slam try, 5+ cards.

3♠

Invitational, 6+ cards.

3NT

Forcing to game without slam interest, exactly 5 cards in spades.

4♣!, 4♦!, 4♥!

Splinter, slam try (14+ points), 0~1 cards, 6+ cards in spades.

4♠

Signoff, 6+ cards.

Super acceptance 3♠

3NT

Forcing to game, balanced.

4♣!, 4♦!, 4♥!

Slam try, control bid.

4♠

Signoff, strong enough to play.

Transfer to clubs 2♠!

The special 1NT-2♠; *-3♦ auctions show a slam try with 5+ cards in both minors. This is the only possible case of only 5 cards in clubs.

Relay 3♣

When dissatisfied with 3NT and having a major singleton or void, responder always has a chance to escape because opener is forced. However, with 0~1 card in diamonds, opener may pass the 3NT response. Therefore, dissatisfication must be shown beforehand at 4♦!

3♦

Slam try, 5+ cards.

3♥!

Forcing to 3NT, 0~1 card in spades.

3♠!

Forcing to 3NT, 0~1 card in hearts.

3NT!

Pass-or-correct, 0~1 card in diamonds.

4♦!

Forcing to game, dissatisfied with 3NT, 0~1 card in diamonds.

Super acceptance 2NT

After a super acceptance, responder can upgrade some weak hands to game-forcing ones.

3♣, 3NT, 5♣

To play.

3♦

Slam try, 5+ cards.

3♥, 3♠

Forcing to 3NT, previously hidden 4+ cards.

4♣

Slam interest, starting control bidding.

Nevertheless, I found 3♥ and 3♠ unhelpful. I suggest reverting their meanings. The old meanings help decide between 3NT and 5♣.

3♥!

Forcing to 3NT, 0~1 card in spades.

3♠!

Forcing to 3NT, 0~1 card in hearts.

Transfer to diamonds 3♣!

The only rebid of opener is relay 3♦ due to lack of bidding space.

Relay 3♦

3♥!

Forcing to 3NT, 0~1 card in spades.

3♠!

Forcing to 3NT, 0~1 card in hearts.

3NT!

Pass-or-correct, 0~1 card in clubs.

4♦!

Forcing to game, dissatisfied with 3NT, 0~1 card in clubs.

Second responses to a 2NT opener

Since major super acceptances are control bids, there is no need to discuss them here. This section is focused on relays and rejections.

Transfer to hearts 3♦

Relay 3♥

The special 2NT-3♦; 3♥-3♠ auction shows a weak hand with 5+ cards in both majors. Opener always accepts transfer to protect this auction.

3♠

Weak, 5+ spades

3NT

Forcing to game without slam interest, exactly 5 cards in hearts.

4♣, 4♦

Dissatisfied with 3NT, 4+ cards.

4♥

Signoff, 6+ cards.

4NT

RKCB 0314, 6+ cards in hearts.

5NT

Balanced slam force. Opener shall choose between 6♥ and 6NT. Responder may raise to 7.

Transfer to spades 3♥

The special 2NT-3♥; 3*-4♥ auctions show a slam try with 5+ cards in both majors.

Relay 3♠

3NT

Forcing to game without slam interest, exactly 5 cards in hearts.

4♣, 4♦

Dissatisfied with 3NT, 4+ cards.

4♥

Slam try, 5+ cards.

4♠

Signoff, 6+ cards.

4NT

RKCB 0314, 6+ cards in spades.

5NT

Balanced slam force. Opener shall choose between 6♠ and 6NT. Responder may raise to 7.

Rejection 3NT

The Wbridge5 AI rejects with a doubleton, but I suggest opener only reject with a singleton. This rejection generally does not affect bidding structure. However, responder now needs 7+ cards to assume a fit to bid 4♠ or 4NT.

Transfer to clubs 3♠!

New suits are control bids because there cannot be a major side suit.

It is safe to transfer with a slam try with 5-5 minors because opener rejects transfer with 1~2 cards in clubs.

Acceptance 4♣

An acceptance promises 3+ cards, so a good fit is found.

4♦

Control bid or slam try with 5+ cards.

4♥, 4♠

Control bid.

4NT

RKCB 0314.

5♣

Signoff.

Rejection 3NT

A rejection shows a singleton or doubleton in clubs. Responder passes or signs off at 4♣ with a weak hand.

4♣, 5♣

Signoff, 7+ cards.

4♦

Control bid with 7+ cards in clubs or slam try with 5+ cards in diamonds.

4♥, 4♠

Control bid with 7+ cards in clubs.

4NT

Blackwood. No fit is found but responder may assume a fit in diamonds with 5+ cards.

Transfer to diamonds 4♣!

Relay 4♦

Although opener has a singleton in the worst case, there is no way to sign off at 4NT.

4♥, 4♠

Control bid.

4NT

RKCB 0314.

5♦

Signoff.

Super acceptance 5♦

This bid prevents responder from passing the 4♦ relay but consumes too much bidding space. Responder can only bid quantitatively now.