An Open Invitation from WBFLC

This appeared in the World Championships Bulletin No.11. I intend to respond: covering laws that have come up in this blog.

The Laws of Duplicate Bridge – An open invitation

by Grattan Endicott

The WBF Laws Committee is now giving some preliminary thought to the next review of the Laws of Duplicate Bridge. Its first decision is to issue a worldwide invitation to players, tournament directors, and NBOs (and as it may be, other members of bridge discussion groups), to send to me any thoughts they may have as to desirable changes in the Laws.

I intend to divide suggestions received into two categories:

1. those which propose a change in the effect of the law; and
2. those which retain the current effect of the law but target an improvement in the wording and/or layout of a Law.

The broad inclination of the committee as it commences the task is to institute very few category (a) changes but to concentrate mainly on proposals in category (b). All suggestions will receive consideration and we will see what responses this invitation brings.

For ease of identification and sorting, I request:

1. That nothing reaches me before 1st December 2011, and
2. That the subject line of every email shall contain the words “Duplicate Bridge Law”, which may be followed, if desired by a Law number.

Given the likely number of suggestions that will be sent, please do not anticipate an acknowledgement of receipt unless there is something not fully understood. Do not assume that anything received hitherto will be on record — send it afresh if you wish it to have attention.

Invitation issued Tuesday, October 25, 2011.

Responses must be received no later than 31st December 2012.

Send to grandaeval@tiscali.co.uk

Application of Law 12C1(b) revisited

I have been called on a number of times recently to advise on the application of Law 12C1(b) — adjustment for non-offending side following self-inflicted damage, due to a SEWoG. I have written a spreadsheet to display the calculations (feedback welcome). As a consequence of writing the software, I now better understand the calculations and I have rewritten my article, which subsequently appeared in the EBU White Book.

Application of Law 12C1(b)

There are scores (for the non-offending side) we have to consider

1. the score for the Actual table result (including any serious error or WoGA)
2. the score for the result Before infraction (assigned by Law 12C1c)
3. the score for the result that Could have been scored, with the infraction but without serious error

The corresponding scores for the offending side are A', B', C'; at IMPs A' = −A, etc.; at match points A + A' = top, etc.

The overall damage D (= B − A) can be divided as

• Real damage: D_R = B − C
• Self-inflicted damage: D_S = C − A

There are four cases: all damage is self-inflicted, some is self-inflicted, no self-inflicted damage, or no damage at all.

• B ≤ A: no advantage, no damage, no adjustment;
• A < B ≤ C: all damage self-inflicted, no real damage D_R ≤ 0, NOS get A, OS get B';
• C ≤ A < B: no self-inflicted damage, D_S ≤ 0, balancing adjustment, NOS get B, OS get B';
• A < C < B: real damage and some self-inflicted.

In the final case, the OS get B' and the NOS get A + B − C = adjusted score − self-inflicted damage.

Examples

NS bid to 4H and EW “use UI” to compete to 4S, which is doubled. In defending 4SX, NS might revoke (a serious error) and lose a trick they would otherwise score. The result in the other room is NS +50. The expected result in 4H is making, so B (the result before the infraction) is +9 IMP for the non-offending side.

4SX-1 NS +100. Revoke

A = IMP(100-50) = +2 IMP. Without the revoke: 4SX-2 NS +300. C = IMP(300-50) = +6 IMP.

Damage D = 7 IMP; real damage D_R = 3 IMP, self-inflicted damage D_S = 4 IMP.

Offending side (team of EW) get −9 IMP, non-offending side (team of NS) get 2 + 9 − 6 = +5 IMP.

4SX-2 NS +300. Revoke

A = +6 IMP. Without the revoke: 4SX-3 NS +500. C = IMP(500-50) = +10 IMP. No real damage (D_R < 0).

Offending side get −9 IMP, non-offending side get +6 IMP (table result).

4SX-2 NS +300. No revoke

A = C = +6 IMP. No self-inflicted damage (D_S = 0). Both sides get ±9 IMP.

4SX-3 NS +500.

A = +10 IMP. No damage. Table result for both sides.