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Contract Bridge

Scoring

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Scoring of individual deals Edit

The scoring is mostly the same in rubber bridge and duplicate bridge. The elements of scoring are:

  • contract
  • slam
  • overtricks
  • undertricks
  • double
  • game (different in rubber and duplicate)
  • honours (only in rubber)

In rubber bridge, scores are entered above and below the line. Only contract points are entered below the line and counted towards games, all others are bonuses. In duplicate bridge, the elements are added together and represented as a single directed number which can be compared with other tables directly. The aim of rubber bridge is to win the rubber (2 games), while the aim of duplicate bridge is to perform the best among tables playing the same deal.

Understanding the element of scoring is a key to more advanced techniques like sacrificing.

contract Edit

For a contract made, each odd trick (tricks above the first 6 called the book) is 20 points (/) or 30 points (//NT). The first NT odd trick is 40 points. They can be doubled or redoubled. In rubber bridge, they are entered below the line.

slam Edit

A 6-level contract (small slam) bid and made adds 500 points (750 points if vulnerable). A 7-level contract (grand slam) bid and made adds 1000 points (1500 points if vulnerable). They are entered above the line in rubber bridge.

overtricks Edit

When the contract is not doubled, they behave as additional odd tricks, but entered above the line instead in rubber bridge. However, when the contract is doubled, each overtrick is 100 points (200 if vulnerable), doubled if the contract is redoubled.

undertricks Edit

If the contract is set, each undertrick (trick short of contract) is 50 points to the opponents (100 points is vulnerable). However, when doubled, the first is 100, the second and third is 200 each and 300 each afterwards (the first is 200, 300 each afterwards when vulnerable), doubled if the contract is redoubled. They are entered above the line in rubber bridge.

game Edit

When 100 points are accumulated below the line in rubber bridge, a game is finished. A new line is drawn below everything, hence all below-the-line score becomes above-the-line. When a partnership finishes 2 games, they won the rubber and 700 points are awarded if 2-0, 500 points are awarded if 2-1.

In duplicate bridge, all deals are independent. A game is a contract with >=100 contract points. 300 points are added is a game is made (500 if vulnerable). Otherwise, it is called a part score and 50 points are added.

double Edit

A double bonus, or called an insult, worth 50 points for a doubled contract or 100 points for a redouble contract, is given above the line whenever a doubled or redoubled contract is made.

honours Edit

In rubber bridge, if 4 out of the top 5 trumps are held in one hand, he/she may immediately claim 100 points above the line at the end of the deal. If all top 5 trumps or all aces in a NT contract are held, 150 points may be claimed. This is purely an element of luck and some players don't count it.

Examples Edit

Contract Vulerability Result Contract Level Slam Double Overtricks Undertricks Total Remarks
1/1 any = 20 50 70 Lowest scoring contract
7NT vulnerable = 220 500 1500 2220 Highest scoring non-doubled contract
1NTxx vulnerable +6 160 500 100 2400 3160 Highest scoring contract
1NT non-vulnerable -1 -50 -50 Smallest penalty of setting a contract
7NTxx vulnerable -13 -7600 -7600 Largest penalty of setting a contract
/ any 0 Passed out deals are recorded as 0 points

Scoring of rubber bridge Edit

Initially, horizontal line and a vertical line is drawn on a paper to separate it into two columns and two rows. The columns are labelled "we" and "they", or alternately the names. "The line" refers to the horizontal line. Scores are entered above and below the line, only scores below the line count towards games.

The bonus of a rubber is 700 if the rubber is won 2-0, and 500 if won 2-1. If the rubber is unfinished, the side with a game on scores 300, and the side with a partscore on scores 100.

Here is an example of scoring of a rubber (the superscripts are for illustration only and do not exist on real scoring sheets):

We They
5009

15009
807
8006
505
301

1505

1004
4004
1004
503

601
202

2404

805

207

2209 908
3340 1150
  1. We made 2 and get an overtrick, getting 60 below and 30 above.
  2. They just made 1, getting 20 below only.
  3. We bid 1NT but ran down 1, so they got 50 for it.
  4. They went for 3, we doubled, they redoubled and got 11 tricks. They got 240 below for the contract, 100 above for the redouble and 400 for the overtricks. Declarer had AKQJ and claimed 100 above. They had accumulated 100 points below so they got a game and a new line was drawn below. They became vulnerable.
  5. We bid 1NT and they doubled. We just made and got 80 below for the contract and 50 above for the double. However, one of the opponents got all aces, and claimed 150 above.
  6. They bid 4, we doubled and they went down 3. As they are vulnerable, we got 800 above for the undertricks.
  7. We bid 1 and got 11 tricks. We got 20 below and 80 above. We had accumulated 100 points below and got a game. A new line was drawn. Now both were vulnerable.
  8. They bid 3 and just made, getting 90 below.
  9. We bid and made 7NT, a grand slam. We got 220 below and 1500 above. We got our second game and won the rubber, with 500 points added. The final result was 3340-1150.

Scoring of duplicate bridge Edit

There are two main types of duplicate scoring: MP (Matchpoint) or IMP (International Match Point). MP scoring is more common in pairs events and IMP scoring is more common in teams events. Some literature assumed the above[1] but the usage of the other form is also possible.

MP scoring Edit

In MP scoring, a table is compared to every other table, and gets 1 MP for winning, 0.5 MPs for drawing, 0 MPs for losing. (A variant is 2 MPs for winning, 1 MP for drawing, 0 MPs for losing. The effect is identical.) Therefore, for n tables, the maximum possible score is (n-1) MPs, the minimum possible score is 0 MPs.

The application is very easy. It is equivalent to just sorting all the result and sequentially assigning the number of MPs. The average is used for drawing boards.

Usually, the number of MPs is converted to a percentage. An alternate name in team events is board-a-match.

Example in a pair event Edit

Board 1, none vulnerable
Contract Dealer Result NS Points EW Points NS MPs EW MPs
4 S +2 480 -480 7 0
4 S +1 450 -450 6 1
4 S = 420 -420 4 3
4 S = 420 -420 4 3
4 S = 420 -420 4 3
5x W -2 300 -300 2 5
3 S +1 170 -170 1 6
6 S -1 -50 50 0 7

Note that the number of MPs of NS and EW added together must equal (n-1) where n is the number of tables.

Example in a team event Edit

Round 3, opposing team 5
Board Vulnerability Contract Declarer Result Score Opposing MPs
1 None 3 S = 110 110 ½
2 N-S 4 S = 620 170 1
3 E-W 2 E = -110 -100 0
4 All 3NT E +1 -630 -600 0
5 N-S 5 S = 600 -200 1
6 E-W 2 N -1 -50 70 0
7 All 4 E +3 -710 -2210 1
8 None 5x W -2 300 420 0
Total 3 ½ (out of 8)

IMP scoring Edit

In IMP scoring, a table is compared to every other table, and the differences are converted to IMPs by a standard table. The resultant IMPs are added together (and possibly averaged out to reduce inflation). (Other methods also exist, e.g. calculating a datum first and compare the tables to the datum).

IMP table Edit

Point differenceIMPs Point differenceIMPs Point differenceIMPs
fromtofromtofromto
010037042091750199018
20401430490102000224019
50802500590112250249020
901203600740122500299021
1301604750890133000349022
17021059001090143500399023
220260611001290154000 or more24
27031071300149016
32036081500174017

Example in a pair eventEdit

Board 1, none vulerable
Contract Dealer Result NS Points Comparison to other tables NS Total IMPs NS Average IMPs
480 420 420 300 -50
difference IMPs difference IMPs difference IMPs difference IMPs difference IMPs
4 S +2 480 N/A 60 2 60 2 180 5 530 11 20 5
4 S = 420 -60 -2 N/A 0 0 120 3 470 10 11 3.75
4 S = 420 -60 -2 0 0 N/A 120 3 470 10 11 3.75
5x W -2 300 -180 -5 -120 -3 -120 -3 N/A 350 8 -3 -0.75
6 S -1 -50 -530 -11 -470 -10 -470 -10 -350 -8 N/A -39 -7.75

The IMPs for EW is that the opposite for NS, that is, the sum of IMPs gained by NS and EW equals 0. Moreover, the sum of IMPs by NS across all tables must also equal 0.

Example in a team event Edit

This example is the same as above, as to illustrate the tactics between MP and IMP scoring.

Round 3, opposing team 5
Board Vulnerability Contract Declarer Result Score Opposing Difference IMPs
1 None 3 S = 110 110 0 0
2 N-S 4 S = 620 170 450 10
3 E-W 2 E = -110 -100 -10 0
4 All 3NT E +1 -630 -600 -30 -1
5 N-S 5 S = 600 -200 800 13
6 E-W 2 N -1 -50 70 -120 -3
7 All 4 E +3 -710 -2210 1500 17
8 None 5x W -2 300 420 -120 -3
Total 33

Remarks:

  1. Flat board.
  2. Our team made a game but their team failed to bid it. 10 IMPs were won.
  3. It is probably the result of competing in partscores. The 10 point difference was nullified in IMPs but significant in MPs.
  4. Their team on this table gained an overtrick but our team didn't, which was a loss of 1 IMP.
  5. We safely arrived a minor suit game contract but their team arrived at a wrong game, resulting a set. 13 IMPs are won.
  6. We bid too high, resulting a set. They stopped at the 1 level just made. We lost 3 IMPs.
  7. They missed a grand slam. We won 17 IMPs.
  8. They found a good sacrifice. We lost 3 IMPs.

Overall, we won the round greatly. However, at MPs, it would be a loss (see above). Generating large swings for games and slams are very important in IMPs but have little use at MPs.

VP scoring Edit

To further reduce swings produced by opponents with great difference in skill, sometimes, the total IMP difference in a round is converted to VPs (victory points) by using a table. There is no standard VP table. The overall winner is determined by total VPs.

VP scoring is only used in matches with more than two teams.

Tactics Edit

MP scoring emphasises win as often as possible while IMP scoring emphasises win as much as possible. Therefore, tactics are different between these two forms of scoring.

Illustration Edit

Bid game or not?

3+1 170 (170)
4= 420 (620)
That is, a successful game wins 6 (10) IMPs over those who doesn't bid game.

3= 140 (140)
4-1 -50 (-100)
That is, an unsuccessful game loses 5 (6) IMPs over those who doesn't bid game.

Therefore, a game needs only 45% to make when non-vulnerable and 38% to make when vulnerable to break even at IMPs. However, at MPs, anything and only things that have over 50% success rate will get a success in the long run.

Double or not?

4-1 -50 (-100)
4x-1 -100 (-200)
That is, a successful double on a game wins 2 (3) IMPs over those who doesn't double.

4= 420 (620)
4x= 590 (790)
That is, an unsuccessful double on a game loses 5 IMPs over those who doesn't double.

Therefore, at IMPs, usually a double is only made when the contract will surely be set. However, at MPs, this may be a 50/50 bet in hope for generate more tops.

Overall, the competitiveness is higher at MP scoring, including:

Moreover, players strongly prefer NT contracts to major suit contracts if they generate the same number of tricks since the 10 point difference may mean a top rather than an average. Furthermore, the hunt for an overtrick is worthy even at the cost of the contract, since an overtrick may put you on top.

However, at IMP scoring, as the bonuses for games and slams are attractive, more of them are bid and the most important thing is to make the contract as overtricks are nearly worthless (about 1 IMP per overtrick only) unless the contract is doubled or redoubled. Also, the choice of denomination is not as important as in MPs, that is, if you need to choose between 3NT and 5, you just pick the one which is more likely to make.

Recent changes of scoring Edit

Before 1990, each undertrick after the second in a non-vulnerable doubled contract scores 200 to the defenders. However, sacrificing against grand slams was found to be too easy after Jeff Meckstroth bid 7 holding 9xxxx over 7 by Edgar Kaplan and Norman Kay and got down 10 and still got profit, which lead to scoring change to 300 for each undertrick from the 4th. Also, the insult for a redoubled contract was increased to 100 and the bonus of unfinished partscore in a rubber was increased to 100.

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