1. Radlett U3A Duplicate Bridge Workshop
Gary Harding 24th November 2016
Final V1.0

2. Agenda The deals and how they are prepared The movements I use
How duplicate bridge is scored
What information is available on our BridgeWebs site and how you can use it (I will not be able to cover all of this but will at least give an introduction).

3. The deals and how they are prepared
I run the BigDeal (a Windows interface to BigD) programme
Select file name and number of boards
Type a few random characters (the timing of which provides a seed to the PRNG – Pseudo Random Number Generator)
This creates an output in PBN (Portable Bridge Notation) format

4. Example PBN extract % PBN 1.0 [Generator "Big Deal version 1.2"]
[Board "1"]
[Dealer "N"]
[Vulnerable "None"]
[Deal "N:AKJ7542.K4.A T763.KJ7652 QT963.JT865.QJ5. 8.AQ3.K984.AQT93"]
[Board "2"]
[Dealer "E"]
[Vulnerable "NS"]
[Deal "N:K52.J32.Q AQT KJ2 QJT3.K9.KJ84.AT3 A AT.Q974"]
[Board "3"]
[Dealer "S"]
[Vulnerable "EW"]
[Deal "N:T2.T9872.Q9.AK95 Q A876.T7 A9.AQ4.J4.Q86432 KJ73.KJ3.KT532.J"]

5. This can be read by, e.g. Bridge Composer

6. Bridge composer can do double dummy analysis

7. Dealt, e.g. by dealer4 machine

8. Or duplimate (https://youtu.be/6AoVPecJ2Rw)

9. Movements Two basic types of movement, Howell and Mitchel
Howell is best for up to 5 tables, all (or all but 1 pair) move according to a table direction sheet.

11. Movements Two basic types of movement, Howell and Mitchel
Howell is best for up to 5 tables, all (or all but 1 pair) move according to a table direction sheet.
Mitchell – North – South stationary, E-W and boards move in opposite directions
Simple for an odd number of tables, E-W up a table, boards down a table
For an even number of table either need to ‘share and relay’, or skip a table in the middle of the session to avoid EW playing the same boards again

12. Advantages and disadvantages
Howell
+ Can work for as few a 3 tables
+ For a small number of tables you get to play against all (or most of) the other pairs
- no or few stationary positions
- gets complicated and unbalanced if more than 5-7 tables
Mitchell
+ Simple rules to follow
+ With Arrow Switch can get a whole field result
- does not work with less than 5 tables

13. Basic Duplicate Play Each hand is scored similar to rubber bridge
Dealer and Vulnerability is determined from the board
No score for ‘honours’
Hands are put back in the board at the end of each boards play
After each round the boards are moved to a different table to be played by a different pair of players
In a single session no pair plays the same board twice (in some circumstances two pairs may play each other twice ‘a revenge’ but with different boards)

14. Traveller

15. Bridgemate

16. BriAn

19. Scoring
At the end of the session we have the results from all boards played by all pairs something like this:

20. Scoring
This is then sorted into order (in this case worst to best for NS):

21. Scoring
Match points (MPs) are give to NS according to the formula (0 to (number of times played -2) times 2)

22. Scoring
Where there is a tie each pair in the tie gets the average of the MPs

23. Scoring
EW get the top score (in this case 10) less the NS score

24. Real example (Board 2 – 13th October 2016)
Sorted

25. How going off can give you a top! (Board 11 - 22nd September 2016)

26. A slam might only be worth 2 pts more than game
A slam might only be worth 2 pts more than game! (Board 3 – 13th October 2016)

27. A correction might be made
If some boards are played more than others (e.g. due to skips or relays) a Neuburg correction is made so that they are close to equivalent).
E.g. if some boards are played 6 times the top is 10 and some boards are played 7 times the top Is 12 it is unfair on the pairs that played the boards that were played less times. An adjustment is made which would turn the top on the boards that are played 6 times to about (exact number is dependent on a number of factors!).

28. All of the MPs are added up for each pair

29. Correction for number of ‘tops’
If some pairs have played more boards than others (e.g. due to a sit out) absolute number of MPs would not be fair.
So the MPs scored is divided by the maximum number of MPs available to that pair to give a %
This is then used for the rankings!

30. Bridgewebs

40. Or click on board
number
Move to previous board
Move to next board
High card points
Best contract analysis
Play hand again
Final scores by all pairs and MPs

47. Questions?