bd71, on 2012-April-19, 22:34, said:
Do you recommend this only in this auction, in any (1y)-2x-(2y) auction, or even more broadly (and if so, please specify)?
As a minimum, I recommend it in any auction where you don't have any other cue-bid available below three of partner's suit. (1y)-2x-(2y) is the most common example of this, but there are a few others:
(1
♥) 2
♦ (2
♠)
(1NT) 2
♠ (pass)
(1
♦) 2
♦[nat] (pass)
There's a good case for extending this to other sequences, but the value in doing so varies according to the sequence:
- After (1x) 1y (2x) or eg (1
♦) 1
♥ (2
♠) you have only one cue-bid available, so it's beneficial to add 2NT to let you distinguish 3- and 4-card raises.
- When responder has bid a new suit between the opened suit and the overcalled suit, you have two cue-bids. Using 2NT lets you show a 3-card raise, a good 4-card raise, a mixed raise and a weak raise.
- When he's bid a new suit below the opened suit there are three (one of them below the two-level). Adding a fourth one isn't especially useful.
- When he's passed or bid 1NT there are two (one below the two-level). Using 2NT gives you a third raise, but you're less likely to need it than in some other sequences.
One approach is to make rules based on the number of cue-bids you have available. I've been persuaded that it's easier just to play 2NT as a raise in all these sequences, except specifically when we've overcalled in a minor and we have at least one cue-bid available.
Having decided which bids show a raise, you need rules for what they mean. I suggest something like:
- With one artificial raise available, it shows any good raise and a jump raise is mixed (or weak if you prefer).
- With two artificial raises available, the lower is a good 3-card raise, the higher is a good 4-card raise, and a jump raise is mixed.
- With three artificial raises available, the lowest is a good 3-card raise, the middle a good 4-card raise, and the highest a mixed raise.
- With four or more artificial raises available, the lowest is a good 3-card raise, the next lowest is a good 4-card raise, the highest is a mixed raise, and anything else is a splinter.