[SeanBothar]

Many Bridge clubs are now having to play their weekly games online and are interested in the type of Howell used by BBO.
Most of our Bridge movements are derived from those used in the United States for duplicate Whist in the 1890s onwards.
(John) Mitchell, (Edwin) Howell and American Whist are familiar terms.
Less familiar is Flower who devised a Howell type movement where pairs move regularly but the board movement is complex.
BBO uses Flower Howells and the board movement problem doesn't arise as the same boards are played at all the tables each round.
In a BBO Flower movement, Pair 1 stay at table 1 as NS throughout.
The other NSs move up a table and the EWs move down a table after each round.
When the NSs finish playing at the last table they switch to EW at this table.
When the EWs finish playing at table 1 they move to table 2 as NSs.
This applies to all BBO Flower Howell movements up to 20 tables (the current maximum permitted).

[RayFink]

From what I've seen, the larger BBO Howells are seeded very poorly (if seeded at all) if you are not playing complete Howell movement.

Does anyone have information on how well (pun intended) these movements are balanced?

[SeanBothar]

RayFink, on 2020-June-17, 11:24, said:

From what I've seen, the larger BBO Howells are seeded very poorly (if seeded at all) if you are not playing complete Howell movement.

Does anyone have information on how well (pun intended) these movements are balanced?

In a complete or full Howell all pairs play against each other.
So for a 6 table complete Howell each pair plays against 11 others and if 2 boards are played a round then 22 boards in total (6T 11R 22B).
To balance this movement consider pair A who played 2 boards against pair B.
For the other 10 rounds when they didn't play against each other A & B should be on the same side of the travelling scoresheet 10 times and on the opposite side 10 times for 20 boards.
If this applies to all the other pairs then the balance is 100%.
As mentioned for BBO Flower Howells all tables play the same boards for each round.
This is also used in BBO Mitchells (see previous post BBO Mitchells - switching).
Balancing a complete or full BBO Flower Howell is much easier than a BBO Mitchell.
Usually a whole table is switched for all the rounds.
For example if table 3 is switched then the moving NS pair who arrive here from table 2 play as EW and the moving EW pair from table 4 play as NS.
Listed below are the balance percentages before and after switching for complete (full) 3 to 8 tables BBO Flower Howells.

3T 5R no improvement with switching 60% unswitched
4T 7R switch table 4 100% compared to 53% unswitched
5T 9R switch table 5 83% compared to 50% unswitched
6T 11R switch table 3 100% compared to 48% unswitched
7T 13R switch table 5 91% compared to 47% unswitched
8T 15R switch 5,6,7 & 8 100% compared to 60% unswitched

Whether it is possible to apply this changes to the BBO coding is another matter!

[criptik]

I've seen that there are flags that can force Howell movements for Clocked tournaments, but in our own small group tournaments we like to play Unclocked. So far, have run maybe 15 or so tournaments over the past 2 months, from 3-5 tables, always Unclocked, so never using the forced Howell flag. And assuming I set up the rounds so that there are as many rounds as one less than the number of pairs, we have never had a case where someone plays the same pair twice. Have we just been lucky or is the default unclocked behavior for small table counts?

[0 carbon]

The Mitchell movement allows 1 NS winner and 1 EW. Why is this better than BBO default of 1 winner?

The Howell movement allows 1 winner, but needs board count and player count restrictions to reach this. Why is this better than BBO default of 1 winner?

[Vampyr]

0 carbon, on 2020-July-14, 19:58, said:

The Mitchell movement allows 1 NS winner and 1 EW. Why is this better than BBO default of 1 winner?

The Howell movement allows 1 winner, but needs board count and player count restrictions to reach this. Why is this better than BBO default of 1 winner?

Except for Howell movements, BBO do not run one-winner pair games.