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

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).

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

Example PBN extract % PBN 1.0 [Generator "Big Deal version 1.2"] [Board "1"] [Dealer "N"] [Vulnerable "None"] [Deal "N:AKJ7542.K4.A2.84 .972.T763.KJ7652 QT963.JT865.QJ5. 8.AQ3.K984.AQT93"] [Board "2"] [Dealer "E"] [Vulnerable "NS"] [Deal "N:K52.J32.Q763.865 96.AQT84.952.KJ2 QJT3.K9.KJ84.AT3 A874.765.AT.Q974"] [Board "3"] [Dealer "S"] [Vulnerable "EW"] [Deal "N:T2.T9872.Q9.AK95 Q8654.65.A876.T7 A9.AQ4.J4.Q86432 KJ73.KJ3.KT532.J"]

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

Bridge composer can do double dummy analysis

Dealt, e.g. by dealer4 machine

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

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.

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

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

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)

Traveller

Bridgemate

BriAn

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

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

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

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

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

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

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

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)

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 11.8 (exact number is dependent on a number of factors!).

All of the MPs are added up for each pair

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!

Bridgewebs www.bridgewebs.com/radlettu3a

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

Questions?