Bridge project quick links

There are two common variants: "pairs" games and "Swiss teams" games. In a Swiss teams game, two partnerships typically compete as a team of four, though some competitions allow teams of up to six with players rotating in and out. Two teams typically play head to head, with the "International Match Point" (IMP) scale determining the weight of differences in scores on each deal and thus the winner of the head to head match. In a standard pairs game, each partnership follows a pattern of movement that determines which hands it plays, in which direction, against which opponents in a series of "rounds" in which each table typically plays two to five deals. The most common movement is a "Mitchell" movement in which North-South pairs remain stationary, East-West pairs move to the table with the next higher number, and each set of boards moves to the table with the next lower number for each round, and there are separate rankings for the pairs playing in each direction. With a complete movement, all East-West players play against all North-South pairs and every pair plays each set of deals. Smaller games frequently use various "Howell" movements in which most pairs play some deals in each direction and all pairs are ranked together. In either case, standard pairs games usually award a full matchpoint to each pair for each table with a lower score in the respective direction and a half matchpoint to for each other table that achieves the same score on each deal. Organizers of duplicate events may set limits on the nature of the bidding systems that players may use, set the pace and duration of play, and group players of similar interests, skill levels, age, or gender, or combinations thereof. The game variant and associated method of scoring have a significant influence on bidding and card-play strategies. Competitions in duplicate bridge range from small clubs with a handful of tables to large tournaments such as the World Bridge Championships^[1] where hundreds of tables play the same hands. Bridge organizations may define player eligibility and provide country representation in international play.

In duplicate bridge, the same cards are played unchanged at two or more tables, and the results are then compared. Scores at each table are recorded on travelling slips that move with the boards or on pickup slips taken to the director. More recently, wireless electronic scoring is becoming more common. For this, each table has a purpose-built keypad on which players enter the score which is then transmitted directly to the scoring computer, doing away with paper slips. Depending on the type of tournament, after the different scores on a board are compared, the relative scores are converted either to match points (MP) or to international match points (IMP). Regardless of the actual contract, the competitor (pair or team) with the best performance on each board gets the highest number of MP or IMP for that board, and vice versa. The competitor with the highest total number of MP or IMP becomes the winner of the tournament. Thus, even with bad cards, competitors can win the tournament if they have bid better and/or played better than the other players who played the same set of cards. Match points (or (for teams) "Board-a-match") scoring simply awards a team or pair two match points for every other pair that had a lower score playing the same hands on that board and one match point for every other pair that had exactly the same score. (In the USA, the points awarded not 2 and 1, but 1 and ½.) IMPs convert differences in scores using a sliding scale. 0 IMPS are awarded for a 0-10 point difference. This requires slightly different tactics at the table.

Polish Wiki List of Links to American Players

American contract bridge people on the Polish Wiki

Karen Allison

Duplicate bridge

Scoring

Scoring assumptions and conditions

The assessment that a sacrifice bid is likely to be advantageous is based on the following assumptions and conditions:

it is judged that the opponents will bid and make a game or slam contract.
it is judged that the sacrifice bid will fail (i.e., 'go down') but that it will go down by no more than a specific number of tricks.
it is assumed that the sacrifice bid will be doubled (i.e., the penalty points for going down are doubled).
the maximum number of tricks to go down depends upon the relative vulnerability of the sides and the strain of the game or slam contract being bid (or expected to be bid) by the opponents.

In addition, there are four cases with respect to relative vulnerability which affect the expected scoring scenarios:

favourable vulnerability occurs when the opponents are vulnerable and our side is not
equal vulnerability occurs when both sides are not vulnerable
equal vulnerability also occurs when both sides are vulnerable
unfavourable vulnerability occurs when our side is vulnerable and the opponents are not.

Score comparison

Table 2: Points for Making a Game or Slam Contract
Vulnerability of Opponents	Game		Small Slam		Grand Slam
Vulnerability of Opponents	Contract	Points	Contract	Points	Contract	Points
Not Vulnerable	3NT	400	6NT	990	7NT	1520
	4♥ or 4♠	420	6♥ or 6♠	980	7♥ or 7♠	1510
	5♣ or 5♦	400	6♣ or 6♦	920	7♣ or 7♦	1440
Vulnerable	3NT	600	6NT	1440	7NT	2220
	4♥ or 4♠	620	6♥ or 6♠	1430	7♥ or 7♠	2210
	5♣ or 5♦	600	6♣ or 6♦	1370	7♣ or 7♦	2140

Table 1: Penalty Points for Going Down in a Doubled Contract
Vulnerability of Sacrificing Side	Number of Undertricks
Vulnerability of Sacrificing Side	1	2	3	4	5	6	7	8	9
Not Vulnerable	100	300	500	800	1100	1400	1700	2000	2300
Vulnerable	200	500	800	1100	1400	1700	2000	2300	2600

If the expected penalty points lost by the sacrificing side for going down in a doubled contract (Table 1) is less than the expected points to be gained by the opponents for making their contract (Table 2), the sacrifice would be advantageous if all assumptions and conditions prove correct.

Sacrificing against game contracts

Sacrificing Against Game Contracts
Opponents' expected game points			Sacrificer's upper limit in expected penalty points and undertricks when doubled
Vulnerability	Contract	Points	Not vulnerable		Vulnerable
Vulnerability	Contract	Points	Points	Undertricks	Points	Undertricks
Not vulnerable	3NT	400	300	2	200	1
	4♥ or 4♠	420
	5♣ or 5♦	400
Vulnerable	3NT	600	500	3	500	2
	4♥ or 4♠	620
	5♣ or 5♦	600

If the opponents bid and make a game contract, it yields them 600 or 620 points when they are vulnerable and 400 or 420 points when they are not vulnerable, depending upon the strain and assuming no overtricks. Accordingly, a sacrifice will be advantageous if the resultant loss in points is less than these amounts. The table at right summarizes the various relative vulnerability and game contract scenarios; it is assumed that the sacrifice bid will be doubled. Accordingly, one will still receive a positive relative duplicate score if one can go down no more than:

three tricks if relative vulnerability is favourable
two tricks if relative vulnerability is equal^[2]
one trick if relative vulnerability is unfavourable.

Sacrificing against small slam contracts

Sacrificing Against Small Slam Contracts
Opponents' expected game points			Sacrificer's upper limit in expected penalty points and undertricks when doubled
Vulnerability	Contract	Points	Not vulnerable		Vulnerable
Vulnerability	Contract	Points	Points	Undertricks	Points	Undertricks
Not vulnerable	6NT	990	800	4	800	3
	6♥ or 6♠	980
	6♣ or 6♦	920
Vulnerable	6NT	1440	1400	6	1400	5
	6♥ or 6♠	1430	1400	6	1400	5
	6♣ or 6♦	1370	1100	5	1100	4

When the opponents are likely to make a small slam contract, a sacrifice bid which is doubled is viable if one can go down no more than

six tricks if relative vulnerability is favourable against a small slam in a major or notrump
five tricks if relative vulnerability is favourable against a small slam in a minor
five tricks if relative vulnerability is equal where both sides are vulnerable against a small slam in a major or notrump
four tricks if relative vulnerability is equal where both sides are vulnerable against a small slam in a minor
four tricks if relative vulnerability is equal where both sides are not vulnerable against any small slam
three tricks if relative vulnerability is unfavourable against any small slam

Sacrificing against grand slam contracts

Sacrificing Against Game Contracts
Opponents' expected game points			Sacrificer's upper limit in expected penalty points and undertricks when doubled
Vulnerability	Contract	Points	Not vulnerable		Vulnerable
Vulnerability	Contract	Points	Points	Undertricks	Points	Undertricks
Not vulnerable	7NT	1520	1400	6	1400	5
	7♥ or 7♠	1510
	7♣ or 7♦	1440
Vulnerable	7NT	2220	2000	8	2000	7
	7♥ or 7♠	2210
	7♣ or 7♦	2140

When the opponents are likely to make a grand slam contract, a sacrifice bid which is doubled is viable if one can go down no more than

eight tricks if vulnerability is favourable
seven tricks if both vulnerable
six tricks if both not vulnerable
five tricks if vulnerability is unfavourable.

Sacrificing against partscore contracts

Similar reasoning can be drawn for sacrifices against potential partscore contracts and cases where one assumes that the contract will not be doubled.

Burgay

defensive stonwalling truscott page 214

Authenticity of the tape, availability of a transcript

Also known as 'the Burgay tapes' & 'the Burgay-Bianchi affair'

In February 1976, a few months prior to that year's Bermuda Bowl, Leandro Burgay, a leading Italian expert in the '70s, claimed that he had had a telephone conversation with Benito Bianchi, Pietro Forquet's partner in both the 1973 and 1974 Italian World Championship victories, during which Bianchi had discussed signaling methods, using placement of cigarettes in the ashtray or in the mouth, which he used with Forquet.^[3] and that Giorgio Belladonna had used with Renato Mondolfo.^[4]

Burgay gave a tape of the conversation to Luigi Firpo, president of the Italian Bridge Federation (FIGB). The tape contained unusual sounds - “odd clicks as if it had been spliced”^[5] and after listening to it, Bianchi acknowledged that while it was he speaking, the tape had been doctored. Burgay then produced a second tape, this time without the unusual sounds. He had deliberately added the sounds to a copy of the tape to get Bianchi’s admission that the conversation had taken place. Bianchi claimed that the discussion only concerned how a cheating method would be possible, not that it had actually occurred.^[3]

On April 23, 1976 expert Signor Bacicchi reported to the FIBG that the tape was authentic and had not been doctored.^[6] After a subsequent hearing that same day, the FIGB suspended Burgay for six years and Bianchi for six months. It was also announced that the players Belladonna, Forquet and Mondolfo were acquitted of any charges. Until that point, the matter had been dealt with internally by the FIGB, but it became a public scandal days before the start of the 1976 Bermuda Bowl when the incident hit the newspapers.^[3]

Even though Burgay and Bianchi were not members of the current Italian team, Forquet was and the World Bridge Federation decided it was necessary to take some action but there was little they could do before the tournament and simply requested the FIGB to conduct an investigation. The FIGB claimed to have already conducted an investigation but the WBF wanted a written report. A year later at the 1977 Bermuda Bowl in Manila, there was no evidence of the promised FIGB investigation and the WBF proposed to suspend the FIGB from membership in the world organization but instead, gave the FIGB another year to address the matter.^[3]

Before the 1978 Olympiad in New Orleans, a new slate of officials was elected by the FIGB who were able to satisfy the WBF that the required investigation had been performed. The threat of suspension was lifted.^[3]^[7] Alan Truscott later characterized the FIGB actions as "defensive stonewalling by his [Burgay's] national organization".^[8]

The first entry on the matter in The Official Encyclopedia of Bridge was made under CHEATING ACCUSATIONS in its fourth edition (1984)^[9] and remained throughout to the seventh and latest edition (2011)^[10] stating that "The case came to the attention of the WBF, but nothing ever came of it because it was never proved that the tapes were authentic."

Down Tricks

Tricks Down	Vulnerability of Declarer
	Not Vulnerable						Vulnerable
	Not Doubled		Doubled		Redoubled		Not Doubled		Doubled		Redoubled
	Trick Points	Total Points	Trick Points	Total Points	Trick Points	Total Points	Trick Points	Total Points	Trick Points	Total Points	Trick Points	Total Points
1	50	50	100	100			100	100	200	200
2	50	50	100	100			100	100	200	200
3	50	50	100	100			100	100	200	200
4	50	50	100	100			100	100	200	200
5	50	50	100	100			100	100	200	200
6	50	50	100	100			100	100	200	200
7	50	50	100	100			100	100	200	200
8	50	50	100	100			100	100	200	200
9	50	50	100	100			100	100	200	200
10	50	50	100	100			100	100	200	200
11	50	50	100	100			100	100	200	200
12	50	50	100	100			100	100	200	200
13	50	50	100	100			100	100	200	200

VP Scales

20-point scale

IMP Score	0	1-2	3-4	5-7	8-10	11-13	14-16	17-19	20-23	24-27	28+
VPs	10-10	11-9	12-8	13-7	14-6	15-5	16-4	17-3	18-2	19-1	20-0

Example: A team winning by 12 IMPs would receive 15 VPs and their opponents 5.

30-point scale

IMP Score	0	1	2	3	4	5-6	7-8	9-10	11-13	14-16	17-19	20-23	24-27	28+
VPs	15-15	18-12	19-11	20-10	21-9	22-8	23-7	24-6	25-5	26-4	27-3	28-2	29-1	30-0

Example: A team winning by 12 IMPs would receive 25 VPs and their opponents 5.

Blackwood

^{[citation needed]}

Blackwood's original summary

After developing the concept in 1936, Easley Blackwood submitted an article proposing his slam-seeking convention to the The Bridge World magazine but it was rejected.^[11] Nevertheless, it gained awareness and use amongst players and was written about by several authors. In his own first publication on the convention in 1949, Easley Blackwood comments on the entries in books by others and noted that "...in every one of these books, they have it wrong!"^[11] He pointed out several misconceptions and concluded with a fifteen-point summary of the "complete and official" Blackwood Slam Convention.^[12] A synopsis of that summary follows:

In order to make the 4NT ace-asking bid, you must first:
1. think your partnership has sufficient strength for a slam,
2. expect to be able to make at the five-level even if partner has no aces, and
3. be prepared with a sound rebid no matter how partner responds
Partner's responses to the 4NT ace-asking bid are:
1. 5♣ to indicate 0 or 4 aces
2. 5♦ to indicate 1 ace
3. 5♥ to indicate 2 aces
4. 5♠ to indicate 3 aces
When responding, do not count a void as an ace.
Generally, 4NT is ace-asking when your side has bid a suit. There are exceptions:
1. when notrump has previously been bid by partner and he subsequently removes one's four-level suit bid to 4NT
2. when a previous opportunity to employ 4NT as ace-asking has not been taken
When clubs are expected to be trumps, one must have at least two aces to employ 4NT ace-asking and when diamonds are to be trump, one must have at least one ace.
The 4NT bidder is only partial captain of the auction and responder has certain rights:
1. the 4NT bidder sets the level of the contract but partner may correct the denomination
2. when responder has a void in the suit in which he would convey, at the five-level, the number of aces he possesses, he may jump to six of the void suit to convey both the number of aces and the location of the void.
3. when responder has a void and his ace-showing response is in a suit of lower rank than the trump suit, he first tells partner the number of aces he has. If partner signs-off at the five-level, responder may continue to slam if his holding justifies it.
If the 4NT bidder, after hearing partner's response, bids a previously unmentioned suit, responder must bid 5NT to end the auction.
An ace shown by a cuebid by either partner should not be counted in responding to the 4NT ace-asking bid.
A 5NT bid after a response to a 4NT ace-asking bid, asks for kings.
Partner's responses to the 5NT king-asking bid are:
1. 6♣ to indicate 0 kings
2. 6♦ to indicate 1 king
3. 6♥ to indicate 2 kings
4. 6♠ to indicate 3 kings
5. 6NT to indicate 4 kings
To ask for kings via 5NT, one must first ask for aces via 4NT even when possessing all four aces oneself.
A jump to 5NT without employing the 4NT ace-asking bid is the Culbertson Grand Slam Force and obliges partner to bid the grand slam if he holds two of the three top trumps and a small slam if he does not.
If the opponents interfere after the 4NT ace-asking bid, a Pass by responder indicates no aces, the suit one above the opponent's indicates one ace, two above indicates two and so on.
Except in duplicate, the king-asking 5NT bid assures partner possession of all four aces.
After a 5NT king-asking bid, neither partner is captain and either can set the final contract.^[12]

Citation journal

Gray, Robert (1973). Kaplan, Edgar; Rubens, Jeff (eds.). "Those Coups". The Bridge World. 44 (6). New York: 7–12.

^ See also the Bermuda Bowl, the World Team Olympiad and the North American Bridge Championships
^ * Sheinwold, Alfred (1967). Duplicate Bridge. New York: Sterling Publishing Co. Inc.
^ ^a ^b ^c ^d ^e Swanson, John (1998). Inside the Bermuda Bowl. Mission Viejo, CA: John Swanson. pages 233-236.
^ Truscott (2002), page 165.
^ Wilsmore, Avon (2018). Under the Table - The Case Against the Blue Team (1st ed.). Dallas, TX: Hamman and Associates LLC. p. 44. ISBN 978-0-692-17982-6.
^ Truscott (2002), page 166.
^ "A World Bridge Federation Code for Conduct". English Bridge Quarterly (46): 4–5. August 1977.
^ Truscott (2002), page 214.
^ Francis, Henry G.; Truscott, Alan F.; Frey, Richard L.; Hayward, Diane, eds. (1984). The Official Encyclopedia of Bridge (4th ed.). New York: Crown Publishers. p. 59. ISBN 0-517-55272-8. LCCN 84001791.
^ Manley, Brent; Horton, Mark; Greenberg-Yarbro, Tracey; Rigal, Barry, eds. (2011). The Official Encyclopedia of Bridge (7th ed.). Horn Lake, MS: American Contract Bridge League. p. 33. ISBN 978-0-939460-99-1.
^ ^a ^b Blackwood (1949), page 192.
^ ^a ^b Blackwood (1949), pages 252-255.

[1] See also the Bermuda Bowl, the World Team Olympiad and the North American Bridge Championships

[Sheinwold1-2] * Sheinwold, Alfred (1967). Duplicate Bridge. New York: Sterling Publishing Co. Inc.

[Swanson-3] Swanson, John (1998). Inside the Bermuda Bowl. Mission Viejo, CA: John Swanson. pages 233-236.

[4] Truscott (2002), page 165.

[Underthetable-5] Wilsmore, Avon (2018). Under the Table - The Case Against the Blue Team (1st ed.). Dallas, TX: Hamman and Associates LLC. p. 44. ISBN 978-0-692-17982-6.

[6] Truscott (2002), page 166.

[7] "A World Bridge Federation Code for Conduct". English Bridge Quarterly (46): 4–5. August 1977.

[8] Truscott (2002), page 214.

[OEB|4|59-9] Francis, Henry G.; Truscott, Alan F.; Frey, Richard L.; Hayward, Diane, eds. (1984). The Official Encyclopedia of Bridge (4th ed.). New York: Crown Publishers. p. 59. ISBN 0-517-55272-8. LCCN 84001791.

[OEB|7|33-10] Manley, Brent; Horton, Mark; Greenberg-Yarbro, Tracey; Rigal, Barry, eds. (2011). The Official Encyclopedia of Bridge (7th ed.). Horn Lake, MS: American Contract Bridge League. p. 33. ISBN 978-0-939460-99-1.

[BW192-11] Blackwood (1949), page 192.

[BW252255-12] Blackwood (1949), pages 252-255.

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User:Newwhist/sandbox/Project WPCB

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