Natural, Five-card Majors, 2/1
One Diamond always shows a four-card suit, so One Club may be opened with a doubleton. Open One Club with 4-4 in the minors.
1NT is 15-17 in all positions and at all vulnerabilities. 1NT may include a 5-card major or a 6-card minor but will only rarely have a singleton.
2/1 is game-forcing in all uncontested auctions.
A 1NT response may be made on any non game-force but is not forcing. Opener will usually only pass a 1NT response with a weak notrump hand type.
Jump shift responses are strong and game-forcing. They are only made on hands with a strong single suit or on two-suited hands with a primary fit for opener’s suit. If responder bids a new suit at his second turn, that is a cue-bid agreeing opener’s suit.
1M-3M is a limit raise.
Inverted minor-suit raises, forcing to 2NT or 3m. Over 1m-2m, the next step shows a weak notrump hand type. 2NT from opener is FG with the ‘next step’ suit. 3m is unbalanced and non-forcing, jumps are splinters but only forcing to 4m. Other bids are FG and at least quasi-natural. After 1C-2C-2D, 2NT and 3C are non-forcing, Anything else in FG.
1m-3m is pre-emptive.
2D, 2H, 2S opening are natural weak twos. They usually show 6-card suits, except in first seat NV, when they will often be only a 5-card suit and potentially very weak. Two-level responses are natural and strong but non-forcing. Opener usually only passes with a minimum and no fit for responder’s suit. Three-level responses are natural and FG. 2NT asks: opener rebids his suit with a minimum and shows a high-card feature with better than minimum. 3NT shows a non-minimum with a good suit and little outside.
Three-level openings are natural and pre-emptive. Over 3D/3H/3S openings, 4C is RKCB. Over 3C, 4D is RKCB.
3NT opening is ‘Gambling’, showing a solid minor and little outside.
4-level openings are natural.
Over 1NT: 2C is Stayman, 2D/2H = transfers, 2S = clubs (3C shows a fit and 2NT denies one), 2NT = diamonds (3D shows a fit, 3C denies one). After a minor-suit transfer, a new suit by responder shows a shortage. 3C is 5-card Stayman, 3D = 5+C/5+D without a 3-card major FG; 3H = 0-3/1-3 in majors FG, 3S = 3-0/3-1 in majors FG. 4C is Gerber, 4D is 5+H/5+S game only values, 4M is natural and to play. A transfer at the 2-level and a jump to game is non-invitational.
Opener will freely raise responder’s suit with three-card support. After 1m-1M-2M, 2NT is game invitational with only a four-card major, 3NT game values with only a four-card major. New suits are help wanted game tries except for 1m-1H-2H-2S which promises four spades, catering for responder 4-4 in the majors and opener 4-3.
A 1NT rebid is 11-14 and will usually have 1-2 cards in partner’s major. It does NOT deny four-cards in a bypassed major. 2C is a puppet to 2D, which responder will either pass or signoff elsewhere, 2D is any game force, all other bids are invitational, including jumps at 3-level, higher bids are auto-splinters.
A 2NT rebid is 18-19. 3C is a puppet to 3D, over which responder can pass, bid a non-forcing 3M or bid 3NT to show a weak hand with 6+ clubs (4C is then nf), 3D is Staymanic, 3H is a slam try in opener’s suit, 3S is a slam try in responder’s suit.
After 2/1 response, 2NT is 11-14 balanced or 18-19. 3NT is 15-17 with a reason not to have opened 1NT.
A 3NT rebid after a one-level response shows a hand too strong to make a non-forcing jump-rebid in opener’s first suit.
A 2NT opening is 20-22. 3C is Puppet Stayman, 3D/3H are transfers, 3S is a slam try with both minors. Jumps to 4-level are two-up transfers and at least mild slam tries: 4C = hearts, 4D = spades, 4H = clubs, 4S = diamonds. When responder has shown a major, completing the transfer shows a lack of interest and 4NT is RKCB. When responder has shown a minor, 4NT is the weakest action and 5m shows some interest.
KOKISH after a 2C opening: 2C-2D-2NT is 23-24 and non-forcing, 2C-2D-2H-2S-2N is 25+ and all system over 2NT openings apply.
Responder MAY bypass a diamond suit to bid a four-card major if he is not strong enough to bid on over a 1NT rebid. With game-going values, responder bids suits in natural order.
2NT after a 1m opening is invitational without a four-card major.
2NT after a 1M opening is Jacoby, showing at least four-card support and FG. New suits at the 3-level then show shortage, jumps in new suits are natural, 3M shows extra values with no shortage, 3NT is 18-19 balanced, 4M is minimum without a shortage.
Reverses after a one-level response are forcing for one round. The lower of 4th suit and 2NT then encompasses all weak hands (Lebensohl-style). All other bids are FG, including a minimum rebid of responder’s first suit.
All high reverses are FG. Reverses after a 2/1 response show some extra values, although need not be 17+. With a minimum, opener rebids his suit, raises, or rebids 2NT.
Jumps when a bid of a suit one level lower is forcing are splinters, as are four-level bids in lower suits after a 1M opening. Bids in a new suit when opener has rebid his original suit are forcing for one round, so jumps are splinters.
Fourth-suit is forcing to game except at the one-level. 1C-1D-1H-1S can be any non-minimum hand with four spades or 10+ HCP without a spade stopper. Opener bids 1NT or makes a descriptive bid at the two-level (2S shows 4-4-1-4 or 4-4-0-5) with a minimum, or jumps (FG) with extra values.
When responder’s suit is raised, a return to opener’s suit is forcing.
Roman Key-card Blackwood: 1/4, 0/3, 2 no Q, 2+Q.
Exclusion Blackwood only in clear circumstances such as a jump to the five-level in a new suit. Responses are 0,1,2.
5NT after 4NT asks for specific kings. Suit bids at the six-level when the bidder could have found out about kings via 5NT ask for third-round control in the bid suit.
Cue-bids are Italian style, that is the lowest control is shown regardless of whether it is first or second-round control, honor or shortage, and skipping a suit usually denies a control in that suit. The exception is that a shortage control in partner’s main suit is not shown with the first cue-bid.
Unless following 4NT, the default meaning for 5NT is ‘pick a slam’.
Negative, responsive and competitive double through 4D. Beyond that, doubles are value-showing, not penalties.
(1x)-Dble-(1y)-Dble = 4y and some values, 2y = 5y and a hand that would have bid 2y after a pass from RHO.
Game-try doubles where there is no space for any other game try.
After our 1M opening and any competition (a takeout double or an overcall), 2NT is a four-card limit raise or better (ie Jordan after a double). After an overcall, a cue-bid is a three-card raise or better. Direct raises to any level are pre-emptive. A new suit is forcing for one round, not game forcing. New suits at the three-level are game-forcing,
Similarly, 2NT after a major-suit overcall from partner is usually a four-card-limit raise or better, and a cue-bid is a three-card raise. However, if there is no room for a cue-bid below opener’s suit at the three-level, then 2NT encompasses all invitational raises: eg (1S)-2H-(2S)-?
Any jump in a new suit below game in a competitive auction (or by a passed hand) is fit-showing. Thus, 1D-(1H)-2S shows 5+S/4+D but is nf, whereas 3S would show the same shape but FG. 1S-(2C)-3D is a limit raise (or a slam try) with 4+S/5+D and 4D is the same shape but a raise to game. By a passed hand, any new suit at the 3-level (even if a non jump) is fit-showing, whether auction is contested or not.
After a 1m opening and an overcall, 2NT is natural and invitational, a cue-bid is a limit raise or better, raises are pre-emptive, new suits are forcing for one round, and new suits at the three-level are FG.
Jumps in the opponents’ suit are splinters.
Lebensohl after interference over our 1NT (opening or overcall), in response to takeout doubles of weak two openings, and after a double of 2M when the opponents have opened a Multi. Going via 2NT shows a stopper (direct 3NT or cue-bid deny) whilst bidding 3NT denies interest an unbid major(s) and cue-bidding shows four cards in an unbid major. Most relatively balanced hands with no stopper will start with a takeout double after a natural overcall of partner’s 1NT opening.
We open 1NT and they overcall. Double is takeout of the suit BID. Pass and then double is also takeout and thus implies length in the first suit bid.
2NT is rarely natural in competition, except as defined above. Possibilities include an invitational raise (as defined above), Lebensohl type, or scramble (if game values have already been denied). 2NT by opener is Lebensohl (Good//Bad) where game possibilities still exist. For example, 1H-(1S)-X-(2S)-? 2NT is weak and competitive in one of the minors and 3m shows extra values.
We double their Stayman or transfer bid. If 1NT is 14+ then double shows the suit bid. If 1NT is a maximum of 15 HCP, double is a penalty double of 1NT.
2NT after a major-suit overcall is an invitational raise as defined above. After a minor-suit overcall, 2NT is natural and invitational and a cue-bid is a limit raise or better. New suits are forcing for one round.
Weak jump overcalls (bearing in mind the vulnerability). Intermediate in fourth seat.
Michaels cue-bids: 1m-2m = Majors. 1M-2M = oM plus a minor, 3C is p/c, 2NT is invitational plus (3m = that minor and weak, 3M = linked minor and extra values).
Against all pre-empts, takeout doubles with Lebensohl responses after two-level openings.
Over 2M/3M openings and also (1M)-Pass-(2M), (1M)-Pass-(3M) and (2M)-Pass-(3M): 4m = bid minor plus oM at least 5-5. When the opponents’ suit is diamonds, 4C = C+M, 4D = Majors. When the opponents suit is clubs, 4C = Majors, 4D = D+M.
Against a weak notrump (opener denies more than 16 HCP), double = penalties, 2C = majors, 2NT minors or FG two-suiter, others natural.
Against strong notrump (opener’s range includes 17 HCP) and against any range of 1NT opening by a passed hand, double = one minor or both majors, 2m = bid minor plus a major, 2M natural, 2NT both minors or FG two-suiter.
Against a Strong Club: double = Majors, 1NT = minors. Pass then bid is strong.
One thought on “BBO Prime bidders challenge: System Information”
The Response structure you outline over reverses appears to be ingberman (which uses lowest of 4th suit or 2N depending on which is cheaper), not Lebensohl (2N always triggers weak sequence). You might want to clarify.
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