User:Newwhist/sandbox/Project WPCB/Bidding and play

=Transfers following a double= When partner opens 1NT and the intervening opponent doubles, there are several variations as to the meaning of responder's actions.
 * 1) Notwithstanding the meaning of other actions, most agree that Stayman is 'on' and a response of 2 over the double is Stayman.

sometimes depending upon whether the double is for penalty or has another conventional meaning, such as in DONT where it shows a one-suited hand.

Opinions vary as to the other The Double is for penalty (Note: some partnerships use a "forcing pass" by the partner of the 1NT opener. The 1NT opener is then obliged to redouble. The partner of the 1NT opener may then pass the redouble with a good hand and 1NT redoubled is judged to be makeable, or with a poor hand initiate bidding 4-card suits up-the-line until at least at 4-3 suit fit is found). =Combinations= See main article Suit combinations.
 * 1) Systems are 'off': Transfers and Stayman become inoperative, i.e. all 2-level bids are for take-out. This has the advantage of simplicity but the disadvantage that the stronger hand becomes dummy with a resultant offering of information to opponents, though conversely responder's hand which could have a wide range of possible strengths is completely concealed from opponents.
 * All 2-level bids become transfers according to this scheme (known as "exit transfers" in some quarters):
 * redouble transfers to 2.
 * 2 transfers to 2.
 * 2 transfers to 2.
 * 2 transfers to 2.
 * 2 (Acol - I have 11 HCP) transfers to NT at the appropriate level.
 * 2NT (Acol - I have 12 HCP)

The Official Encyclopedia of Bridge
First edited by Eric Crowhurst and presented, with corrections, in each subsequent edition of The Official Encyclopedia of Bridge (OEB),      the options for the line of play of a particular suit combination is considered in two ways: (1) from the angle of safety plays, the number of tricks required is given together with the appropriate play and the percentage prospects, and (2) where no particular number of tricks is required but declarer simply wants to do as well as possible, the indicated maximum play (Max) is given with the expectation of tricks if this line is followed.

The lines of play presented in the OEB are based on the absence of any information about the lay of the opponent’s cards. In practice some information may be inferred from the bidding or prior play. In addition, which line of play is chosen will depend upon declarer’s objectives given the method of scoring and his willingness to accept a greater risk of failure for a greater reward.

Missing the ten
The best line of play in contract bridge for a single suit in isolation in which declarer and dummy lack the ten but possess the ace, king, queen and jack. The line of play varies depending on how many cards are held by the defence, and the required minimum number of tricks. The probability of success is also shown.

Declarer and dummy hold six cards combined

 * x - AKQJ9||5||Cash the top honours (mp)||0.719
 * x - AKQJ8||5||Cash the top honours (mp)||0.636
 * x - AKQJx||5||Cash the top honours (mp)||0.622
 * }
 * x - AKQJx||5||Cash the top honours (mp)||0.622
 * }
 * }

Declarer and dummy hold seven cards combined

 * rowspan="2"|x - AKQJ9x||6||Cash the top honours (mp)||0.864
 * 5||Finesse the 9||0.993
 * xx - AKQJ9||5||Cash the top honours (mp)||0.871
 * Jx - AKQ9x||5||Cash the top honours (mp)||0.871
 * xx - AKQJx||5||Cash the top honours (mp)||0.840
 * Jx - AKQxx||5||Cash the top honours (mp)||0.840
 * }
 * Jx - AKQ9x||5||Cash the top honours (mp)||0.871
 * xx - AKQJx||5||Cash the top honours (mp)||0.840
 * Jx - AKQxx||5||Cash the top honours (mp)||0.840
 * }
 * Jx - AKQxx||5||Cash the top honours (mp)||0.840
 * }

Declarer and dummy hold eight cards combined

 * x - AKQJxxx||7||Cash the top honours (mp)||0.961
 * xx - AKQJ9x||6||Cash the top honours, but finesse the 9 if rho shows out in first round (mp)||0.980
 * xx - AKQJxx||6||Cash the top honours (mp)||0.961
 * xxx - AKQJ9||5||Cash the top honours, but finesse the 9 if rho shows out in the first round (mp)||0.980
 * xxx - AKQJ8||5||Cash the top honours, but repeat the finesse to the 8 if rho shows out in the first round (mp)||0.980
 * xxx - AKQJx||5||Cash the top honours (mp)||0.961
 * }
 * xxx - AKQJ9||5||Cash the top honours, but finesse the 9 if rho shows out in the first round (mp)||0.980
 * xxx - AKQJ8||5||Cash the top honours, but repeat the finesse to the 8 if rho shows out in the first round (mp)||0.980
 * xxx - AKQJx||5||Cash the top honours (mp)||0.961
 * }
 * xxx - AKQJx||5||Cash the top honours (mp)||0.961
 * }

Suit combinations =WBS= The Bridge World Standard (BWS) is a bidding system in the card game contract bridge, first developed and serially published between 1967 and 1969 by The Bridge World magazine. It has been updated periodically.

Purpose
Like the Standard American Yellow Card (SAYC), it was intended "for use by impromptu or casual partnerships" and "as a basis for discussion by those who wish to formulate their own system."

Updates
The system was updated as the BWS 1984, BWS 1994,BWS 2001 and BWS 2017 editions. It is based on majority preferences of poled experts and readers of the magazine.

The system shares some similarities with Standard American and 2/1 game forcing, but with many advanced treatments.

Refs

Origins
The development of the Grand Slam Force by Ely Culbertson in 1936 was first published in The Bridge World magazine under the byline of his wife Josephine Culbertson; accordingly, the convention may be referred to as Josephine in Europe

Modern variants or Extensions
Blackwood had not evolved into what has become the standard: Roman Keycard Blackwood (often called RKCB). Using KCB, there are 5 keycards -- the four aces and the king of trumps. The responses to 4NT are: 5C = 1 or 4 keycards; 5D = 0 or 3 keycards; 5H = 2 keycards without the Queen of trumps; 5S = 2 keycards with the Queen of trumps. As you can see, there is no need to bid 5NT to ask for the A, K, and Q of trumps. These days, the only time the Grand Slam Force is used is when partner opens the bidding or when the opener and responder have voids. In fact, 5NT is now used almost exclusively as "5NT Pick-A-Slam."

When this convention is in force, a bid of 5NT (five notrump), when it does not conflict with other conventions used by that partnership (e.g., a 5NT Blackwood bid), is forcing to slam in the suit last bid, unless the trump suit has already been agreed on earlier in the auction. The partner of the 5NT bidder bids as follows:
 * 6 of the agreed trump suit if holding one of the top three trump honors (e.g., the ace)
 * 7 of the agreed trump suit if holding two of the top three trump honors (e.g., the king and queen)

Actually, the previous sentence is the way the convention used to be used -- but these days, respond 7C with 2 of the top 3. Maybe partner has his own trump suit which is better than opener's, but responder has potential losers in opener's suit.

For example, if a partnership is using the Grand Slam Force and one member bids 1 and his partner bids 5NT, it is implied that hearts are the desired trump suit. The original bidder will sign off in 6 with one of the top three heart honors and 7 with two of the top three heart honors.

As with all bidding systems, the Grand Slam Force has its limitations, not the least of which is that the chances of employing it directly over an opening one-bid are extremely rare and 5NT must be understood to be the GSF in other situations. Numerous variations of the convention have been developed.

=Lebensohl=

History
While its originator is unknown, Lebensohl first appeared in late 1960's along with initial variations on its spelling.

In October 1965, The Bridge Journal magazine reviewed an auction where partner’s 1NT opening was overcalled with 2 by right-hand-opponent (RHO). The article highlighted weakness in the ability of the bidding to determine if the opening side had a spade stopper in pursuit of a game bid in 3NT; no satisfactory approach was identified and the authors concluded that: "...this fairly common problem deserves more study by the active theorists."
 * Origins

The first know publication of details of the convention is a 1970 article in The Bridge World magazine by George Boehm which included anecdotal commentary on what was thought to be its origins. Boehom wrote that "About a year ago, in preparation for a Swiss Team event"... he and his partner son, Augie, refined their convention card to include the entry..."Lebensohl when you overcall our notrump opening." Later, a 1987 book on the convention stated: "According to international authority Edgar Kaplan, the true history of Lebensohl has been lost forever. Sometime in the late 60’s, it began to appear on convention cards …"

The convention was first published with a lower case spelling.
 * Spelling

The November 1970 article by George Boehm is recognized as the first published on Lebensohl. In it, Boehme recounts that in preparation for a competition in New York in late 1969, his convention card had the entry "Lebensohl when you overcall our notrump opening..." .

"...thought to be the brainchild of Kenneth Lebensold (whose name had been misspelled). However, Lebensold emphatically denied any part of the convention's development. For lack of a better name, George Boehm appropriated the misspelling and introduced 'lebensohl' in The Bridge World, (November, 1970)."

The November 1970 Bridge World article by Boehm was the first published on Lebensohl[6] but he does not attribute the convention to Ken Lebensold in it. However, Boehm does recount that in preparation for a competition in New York in late 1969, his convention card had the entry "Lebensohl when you overcall our notrump opening". Ken Lebensold was also a competitor at the event and upon reviewing Boehm's convention card, "disowned the convention". Boehm goes on to state that therefore he and his playing partner (son, Augie) "have decided to designate it "lebensohl" and to continue to use it without fee or license".[6]

Notwithstanding Boehm naming and spelling it uncapitalized, most bridge literature refers to the convention as Lebensohl with occasional post-1970 use of Lebensold going uncorrected.

Entries in various editions of The Official Encyclopedia of Bridge were updated as better understandings as to the origin of the convention emerged. The Official Encyclopedia of Bridge (OEB) first listed and described LEBENSOHL in its third edition published in 1976, with no entries in the first (1964) and second (1971) editions.

This third edition, attributed its design to George Boehm;[3] the fourth OEB edition, under the entry LEBENSOLD, states that George Boehm first described the convention and that Boehm had wrongly attributed it to Ken Lebensold;[4] the fifth and sixth editions state likewise but under LEBENSOHL. In the seventh edition and for the first time, the OEB notes

"Uniquely amongst bridge conventions, it should arguably be spelled with a lowercase first letter – lebensohl."[5] and it was thought to be the brainchild of Kenneth Lebensold (whose name had been misspelled). However, Lebensold emphatically denied any part of the convention's development. For lack of a better name, George Boehm appropriated the misspelling and introduced "lebensohl" in The Bridge World, (November, 1970).


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