Cater calls and alerting
A "cater call" is a call made in a situation where either you can't remember your partnership agreement, or else the situation is undiscussed and there are two or more reasonable interpretations for partner's previous call or your current call; however, your call is the same in both situations.
A recent example: (1NT), 2S!, (P), 2NT; (P), 3H!. My 2S, although natural, was alerted due to guaranteeing much less strength than the opponents might expect (we have a stronger way to bid spades, and the weaker path can be done on as little as a 6-count if the suit is good). As a consequence, partner nearly always passes, so the 2NT bid was unexpected and had never come up before.
There were two plausible meanings in our partnership; a) natural, b) Ogust (which is what 2NT normally means after a weak two, in our partnership).
My hand had fairly dubious spades, a side 4-card heart suit, and was at the top of the range for the 2S call. So I reasoned as follows:
- If partner bid 2NT as a natural invite, then I want to accept the invite, but should probably show my side heart suit in case partner has a fit. So the correct call is a natural 3H.
- If partner bid 2NT as Ogust, then I have a maximum but the values are mostly outside spades. So the correct call is an entirely artificial 3H, showing a good hand with bad spades.
As such, despite being on dodgy ground in terms of partnership agreement, my next call was obvious.
What wasn't obvious, however, was how to alert it. We were playing online, so I couldn't see any alerts that partner might or might not have made. Normally the UI from partner's alerts interferes with the play of the hand, but it also has the helpful side effect that it avoids misinforming the opponents.
In this case, my call was undiscussed, but there was a lot of relevant partnership agreement that needed to be disclosed to the opponents about the possible meanings. Of course, it was impossible to fit all this into the fairly small space allowed for alerting on BBO.
A similar example came up recently when the opponents had intervened artificially over our 1NT opening; I didn't know whether 2NT was agreed as Lebensohl or natural, but I had a 2NT bid either way, and decided I'd figure it out how my partner had taken it depending on whether or not they replied 3C. At least this time, "Lebensohl? undiscussed" fit into the alert box, and was hopefully clear enough that the opponents could figure out what was going on, but it might have been missing the implication that I had a non-Lebensohl 2NT bid in addition to a Lebensohl 2NT bid.
Is there guidance for how cater calls should be alerted when using self-alerts (online or behind screens)? What about alerting partner's possible cater call when behind screens? (Obviously, when not using screens, you simply make use of UI to inform the opponents correctly, because this is one of the purposes for which UI can legally be used.)
Comments
I have no experience with the rules for screens, but at least for online the simplest way is normally something along the lines of "Mostly undiscussed...". You can update the explanation as many times as you like so you could then "change" it to "Ask me if you have Qs in chat" or something like that. That way you give the opponents as much notice as possible that additional information is available if they ask for it.
Similarly, if a bid showed hearts (for example) primarily but had multiple additional meanings, I would start with "Hearts + Other options, ask me if Qs" just to avoid misleading the opponents. It would depend to an extent on the type of event you were playing in though - in a friendly club environment with inexperienced BBO users, there is probably more of an argument for putting a note in the chat (or even messaging both opponents directly) to avoid any confusion.
Explain it as 'undiscussed: trying to show hears'
Private chat to opponents 'if 2NT is ogust, then 3H is artificial, but doesn't show what I've got'
Well, this is the other way round from that example: if 3H were misinterpreted as artificial, the artificial meaning would in fact match my hand. That makes it easier to make the call, but harder to alert it.
I guess similar techniques work in either case, though.
At the table, my approach was to explain the potential artificial meaning of the call with a disclaimer; I left it up to the opponents to deduce that it might be interpreted as a natural call (and that it would match my hand if it were). That doesn't seem perfect in terms of disclosure but it was about the best I could manage.