Bridge scoring


Bridge scoring is keeping score in contract bridge. There are two main categories of scoring: duplicate and rubber scoring. While based upon the same basic elements of scoring, they differ in how the elements are applied to individual deals and in how these are then totaled. Chicago, being a variant of rubber bridge, uses an adaptation of rubber bridge scoring. Duplicate bridge has many variations for scoring, comparing and ranking the relative performance of partnerships and teams playing the same deals as their competitors.

Terminology

The following terms and concepts, defined in the glossary of contract bridge terms, are essential to understanding bridge scoring:
Bridge scoring consists of nine elements. Not all elements are included in all game variants and the method of accumulation of the elements over several deals varies.
If the contract is made, the score for each such deal consists of:
If the contract is defeated, the defenders receive
In rubber bridge only,
In duplicate bridge only,
Contract points are awarded for each odd trick bid and made. Their values depend on the suit and whether the contract is doubled or redoubled; they are not affected by vulnerability. Tricks won beyond that necessary to fulfill the contract are referred to as and [|their scoring points] are accounted for separately because their values are dependent upon declarer's vulnerability.

Overtrick points

When declarer makes overtricks, their score value depends upon the contract denomination, declarer's vulnerability and whether or not the contract is undoubled, doubled or redoubled. In an undoubled contract each overtrick earns the same as in contract points ; values increase significantly when the contract has been doubled or redoubled, especially when vulnerable.

Slam bonus

Bonuses are awarded for all contracts bid and made:
When a doubled or redoubled contract is made, a bonus is awarded to the declaring side. It is colloquially referred to as a bonus for "insult", meaning that the opponents have insulted the pair by suggesting that the declarer will not make the contract.
In scoring notation, a doubled contract is indicated by an 'X" after the contract ; a redoubled contract is indicated by "XX".

Penalty points

When a contract is defeated, penalty points are awarded to the defending side. The value of the penalty depends on the number of undertricks, whether the declaring side is vulnerable or not vulnerable and whether the contract was undoubled, doubled or redoubled.
Without a double or redouble, every undertrick has a fixed cost of 100 or 50 points. The scores for doubled undertricks are such that after the first vulnerable undertrick, n vulnerable undertricks cost the same as n+1 undertricks when not vulnerable; for example, four undertricks when doubled and not vulnerable cost 800 points, the same as three undertricks when doubled and vulnerable.

Rubber bonus

In rubber bridge only, a bonus is awarded at the conclusion of the rubber as follows:
In rubber bridge only, a bonus is awarded for any one hand holding four or five of the, i.e. an ace, king, queen, jack or ten.
Honors may be declared and scored at any time after the auction but for strategic reasons it is best to do so at the conclusion of play so as not to give the opponents information about the lay of the cards. Honors may be held by any of the four players, including dummy.

Game or part-game bonus

In duplicate bridge only, game and partial-game bonuses are awarded at the conclusion of each deal as follows:

The score sheet

Rubber scoring is tallied on a score sheet divided into four parts where each partnership accumulates points either or.
The objective is to win by scoring the most total points in the rubber; the rubber is completed when one side has twice accumulated 100 or more contract points below the line.
Only contract points are recorded below the line; all other points are recorded above the line. Any of the four players may be the recorder, his side being represented in the "We" column and the opponents in the "They" column. In the ensuing examples, South is the recorder.

An example rubber

The following table summarizes the results of a rubber consisting of six deals.
The following panels illustrate the progression of the scoring on the score sheet.
Deal 1: South bids 2NT making 3. Only the contract points are scored below the line; the overtrick points are scored above the line.
Deal 2: West bids and makes 4. This scores 120 contract points below the line; since there are no overtricks, no points are scored above the line. The accumulation of 100 or more points below the line constitutes the end of the first game and is signified by the drawing of a horizontal line. Since no part-game or game bonus is awarded in rubber bridge, East-West do not receive an additional game bonus and North-South do not receive any part-game bonus. Furthermore, the part score of 70 by North-South is no longer available for accumulation towards a game by them; the 70 points are said to be "cut off" as signified by the drawing of the horizontal line. Having won a game, East-West are for all subsequent deals of the rubber meaning that they are now eligible for a larger rubber bonus if they win a second game before their opponents win one and they are susceptible to increased penalties if they are defeated in a contract.
Deal 3: West bids 5 and goes down 2, vulnerable, undoubled. This scores 200 penalty points for North-South above the line.
Deal 4: South bids 4 doubled, not vulnerable and makes 5. North-South score 240 contract tricks below the line, 100 overtrick points above the line and 50 points for 'insult' above the line. Accumulating 100 or more points below the line constitutes the end of the second game, signified by the drawing of a horizontal line. Having won a game, North-South are now also vulnerable for all subsequent deals of the rubber.
Deal 5: North bids 3 and makes 4 scoring 60 contract points below the line and 20 overtrick points above the line.
Deal 6: East bids and makes 6 - a small slam holding all five top honors. This scores a game of 120 contract points and earns a slam bonus of 750 points above the line. 150 honor points are scored above the line for holding all five honors. Having again accumulated 100 or more points below the line, East-West win a second game; a horizontal line is drawn to end the rubber.
Rubber Bonus: At the conclusion of the rubber, a rubber bonus is awarded. In this case, East-West have won a slow rubber and receive a 500-point rubber bonus above the line.
Total: The scores for each side are totalled and East-West win the rubber.

Duplicate bridge

Scoring in duplicate bridge is done in two stages:
  1. Each deal is scored as in rubber bridge but with some variations in methodology.
  2. The result of each deal by each partnership is compared to all other results for the same deal by all other partnerships.

    Scoring deals

In duplicate scoring, the score for each deal is independent from all others and is a single number resulting from the addition of points awarded in accordance with either of two cases:
In duplicate bridge, the dealer and the status of vulnerability for each side is predetermined by the board, there being sixteen possible combinations.
BoardDealerVulnerabilityDeclarerContractMadeDownContract
Points		Overtrick
Points		Slam
Bonus		doubled
Bonus		Penalty
Points		Game
Points		Total
N-S		Total
E-W
1N-E13302×30=6050−140140
2EN-SN4 X2+=500−500500
3SE-WN242×20=402×20=4050130−130
4WBothW1NT3402×30=6050−150150
5NN-SS3NT1100−100100
6EE-WS343×30=903050170−170
7SBothW333×20=6050−110110
8W-E777×30=2101000300−15101510
9NE-WN4 X42×=24050300590−590
10EBothE2NT240+30=7050−120120
11S-N666×20=120500300920−920
12WN-SE232×20=402050−110110
13NBothW4 X X42×2×=480100500−10801080
14E-S5150−5050
15SN-SE454×30=12030300−450450
16WE-WN3NT340+=100300400−400

Comparing deals

Matchpoint scoring

One common form of pairs scoring is by matchpoints. On each, a partnership scores two matchpoints for each other partnership that scored fewer points with the same cards, and one point for each other partnership that scored the same number of points. Thus, every board is weighted equally, with the best result earning 100 percent of the matchpoints available, and the worst earning no matchpoints; the opponents receive the complement score, e.g. an 80% score for a NS pair implies a 20% score for their EW opponents. Colloquially, a maximum matchpoints score on a board is known as a "top", and a zero score is a "bottom". The terms "high board" and "low board" are also used.
These matchpoints are added across all the hands that a pair plays to determine the winner. Scores are usually given as percentages of a theoretical maximum: 100% would mean that the partnership achieved the best score on every single hand. In practice, a result of 60% or 65% is likely to win the tournament or come close. In a Mitchell movement the overall scores are usually compared separately for NorthSouth pairs and for EastWest pairs, so that there is one winner in each group.
In board-a-match team game, the matchpoints are calculated using a similar principle. Since there are only two teams involved, the only possible results are 2, 1 and 0 points per board.

International Match Point scoring

In International Match Point scoring, the difference in total points scored is converted to IMPs using the standard IMP table below. The purpose of the IMP table, which has sublinear dependency on differences, is to reduce results occurring from large swings.
The score that is being compared against can be obtained in the following ways:
Example of averaged cross-IMP scoring:
Assume that you are one of five pairs who play Board 2 as North/South where you are vulnerable and the opponents are not. You contract for and make 4, scoring +620, while the other four North/South pairs score −100, −100, −300, and +650, respectively. To determine your average cross-IMP score, create a table like that at right, entering the points scored by each pair as shown. Subtract each of the opponent's scores from yours and enter them in the point difference cells. For each point differential, use the IMP look-up table to determine the IMPs gained. For example, a differential of 720 equates to 12 IMPs, because it falls in the range of 600 to 740 in the IMP table. Adding the IMPs gained gives a total of 37. To determine the average IMPs gained, divide the total by the number of competitors to arrive at 9.25 as your averaged cross-IMP score.

History of contract bridge scoring

Scoring of tricks in notrump contracts

In the 1932 Laws of Contract Bridge, notrump tricks bid and made, and undoubled notrump tricks made but not bid, score 30, 40, 30, 40, 30, 40, 30.
In 1935 this became 40, 30, 30, 30, 30, 30, 30.

Scoring of undertricks

ConditionBefore 19351935-1987After 1987 for duplicate bridge
and after 1993 for rubber bridge
Not vulnerable, not doubled50 each50 each50 each
Not vulnerable, doubled100, 150, 200, 250, 300, 350 etc.100, 200, 200, 200, 200, 200 etc.100, 200, 200, 300, 300, 300 etc.
Vulnerable, not doubled100, 150, 200, 250, 300, 350 etc.100 each100 each
Vulnerable, doubled200, 300, 400, 500, 600, 700 etc.200, 300, 300, 300, 300, 300 etc.200, 300, 300, 300, 300, 300 etc.

Redoubled undertricks have always scored twice as much as the same doubled undertricks.
A change to the scoring of the fourth and subsequent non-vulnerable undertricks, from 200 each to 300 each, was made in 1987 after a hand in the finals of the 1981 Bermuda Bowl. Munir Attaullah and Jane Alam Fazli, playing for Pakistan, reached a vulnerable 7 contract, which would have scored them 2210. But their non-vulnerable opponent Jeff Meckstroth, playing for USA, then sacrificed in 7 on a weak hand with five spades to the jack; this was doubled and went down nine for a score of -1700, a profitable sacrifice. The 1987 change in scoring increased the penalty for down nine when doubled and not vulnerable from -1700 to -2300.
Also, the "insult bonus" for making a redoubled contract used to be only 50. This was changed to 100, so that playing 5 of a minor, redoubled, making an overtrick, is always worth more than an undoubled small slam.

8-level bids

It has always been the intention of every official set of Laws of Contract Bridge to forbid contracts for more than thirteen tricks. Some versions have stated this more clearly than others, but this intention of the Laws has never changed.

International Match Points

International Match Point scoring was developed in Europe; North American players were first introduced to this scoring method at the 1951 Bermuda Bowl match in Naples, Italy. A change to the IMP values was made in 1962.