The beginning of every duplicate bridge session sets a puzzle for the Tournament Director. He or she has to pick out a “movement” or pattern of play consisting of a suitable total quantity of boards, in a suitable number of rounds, that gives the players who have turned up for the session an opportunity to play the highest possible proportion of the boards they can manage in the time, against as many of the other pairs as possible.
If there is an odd number of pairs, there will be a “sit out” round. The TD will try to keep the number of boards per round low so that the sit out time is short.
Suppose ten pairs arrive to play a two and a half hour session of bridge. Generally their pace of play is about 8 boards an hour. It should be possible to play twenty boards. Dividing the boards into rounds of 4 boards would give 5 rounds altogether. The TD might choose that all North South pairs will remain stationary; East West pairs will move “up” one table; and boards will move “down” one table at the end of each round. After two rounds, the boards previously played by a given East West pair will “pass” that pair as they move for round three. The movement will complete when all five East West pairs have visited all five tables and each set of boards has been played at all five tables. Very neat!
This is a Mitchell movement because North South pairs have sat still, and East West pairs have moved up one table. There are many variations on Mitchell movements, but if that is what is (mostly) going on, it’s a Mitchell.
In this case the North South pairs have all played the boards one way, and the East West pairs have all played the boards the other way. It’s effectively two competitions, and is often described as a “two winner” movement with two separate ranked lists.
Suppose that nine pairs had arrived. If you use the above movement, there will be a long sit out round (about half an hour), and some players will play much fewer boards than others. This is a more difficult puzzle. The TD may choose a “Howell” movement.
A Howell movement is based on the principle that the rounds will be shorter, perhaps only two boards, and each pair will play every other pair, making nine rounds of eighteen boards in all. This means that pairs will only sit out for two boards, hopefully about fifteen minutes. All pairs will play sixteen boards. However the room will have to move eight times, taking up time each time. The next step up is 27 boards which could never be played in the time.
Only one pair will remain stationary at a table, and everyone else will find their new position in each round and it may be either North South or East West. There will be no discernible pattern in the table numbers. TIP: Work out which pair you are “following” and look around for where they are at the beginning of each round. Then just go to that place at the end of the round.
Most pairs will play some boards as North South and others as East West, so the results are well “mixed up”. There will be only one ranking list, and this is described as “single winner” movement.
So there are easy solutions to some combinations of time to play and number of pairs, but others are tricky. The TD has a short interval between the time he or she can be sure of the numbers of players for the session and the time the players expect to start playing to choose the movement, set it up on the computer, distribute the boards and pass out the scorers.
So please try and arrive a little before the start of play, or at least make sure that your partner will, to give the TD time to think. A late pair arriving when the movement has a half table may seem a small problem, but from the above, you can see the TD may have made a very different plan for the movement when there is half table and has to decide if they are committed already or whether they change it for a simpler movement, quite possibly allowing more boards to be played.
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