Questions from TD refresher course
I ran a Club TD refresher course on Saturday. During the discussions I was asked three questions which I was unable to answer on the spot, so I promised them I would find the answers and get back to them.
The first was whether a board that had been accidentally arrow-switched could be scored as played in an unswitched Mitchell movement. I could recall the phrase “if the scoring method allows” or something like that, but couldn’t find the regulation. I’ve since found the White Book commentary on law 87 which says the answer is, as I suspected, “no”. (I do wonder what would happen if you tried, though.)
The second was whether a natural 2NT opening bid requires any special disclosure (alert, announcement, prominent warning on the convention card etc.) if it could by agreement contain a singleton. Does it make a difference if the singleton has to be a top honour? I have always considered it routine to open 2NT with a singleton honour if no other bid looks suitable, but I don’t know how that sits with the regulations on disclosure.
The third one is for scoring nerds only, so I’ve posted it in the other forum.
James
Comments
I agree that a 2NT opening that might contain a singleton is not unexpected and doesn't need special disclosure.
For the first question I have had a quick play on a result for a two winner session. EBUScore allows you to do an arrow switch (see the EBUScore Manual page 29) even when the event isn't to be arrow switched. Whether this is correct procedure I don't know. I checked the amendment of the scores and as far as the event I used was concerned the only pairs to have any change to their MPs and percentage were the two that were arrow switched (one pair went up and the other pair went down by the same number of MPs). This is to be expected as the result remains the same on the board. Not sure how or if that will affect the NGS for both pairs (probably insignificant if only one board). One change I tried was to give each pair 50/50 and that resulted in every pair having their result amended on that board. So what does everyone do now for an accidental arrowswitch that involves a 2 winner result? Is there a requlation to cover it? Has it happened much?
CMOT
The regulation is the one quoted by James from the White Book. If you do it, it will have the effect of not all NS scores or all EW scores averaging to 50%. I don't think for one result anyone would bother much how it was dealt with but for lots of them (such as if an incorrect instruction was given to arrow-switch) then it would be best to change it into a one-winner result.
The quote is at the end of WB 8.87.1
"However, the type of contest may make this impossible: for instance, teams of four or two-winner pairs."