Posted 2014-May-31, 10:13
The question implies this is undiscussed. If it had been, there is no question : if you were playing Kaplan inversion you would have discussed this. So it is therefore not natural. A NT continuation would be natural, so therefore it is either heart related or minor related. I rule out the heart-related, because undiscussed, partner can simply raise to invite game.
Regardless, I bid hearts with 7 cards, but assume I have just 6.
You have presumably discussed what 1♥ 3m means, and also 1♥ 1NT 2♥ 3m, so if they are both natural, you probably have one of those as weak and one invitational. In this case I can see no meaning for 2♠ as anything other than both minors, opener taking his choice. An unusual 2NT where here 2NT would be usual, and 2♠ is decidedly unusual. Just pick your minor.
If you were playing 1♥ 3m as heart support of some sort, then the other interpretation of 2♠ would be a single suited minor, weak or invitational, whichever a 3m rebid would not be. This is in addition to the "both minors" interpretation. My opener rebid must then try to cater for both interpretations.
(A) If the "unbiddable minor holding" was weak, then I could bid 3♣ for pass or correct, but equally I could bid 2NT and let partner play. When you incorporate the possibility of it being both minors, then with that I would want 3♣ to be preference. So my eventual opener rebid would be 2NT if I have a preference for diamonds in the 2-suited possibility, and 3♣ otherwise.
(B) If the "unbiddable minor holding" was invitational, I would do the same if I chose to decline a game invitation. However, I cannot do that if I would accept a game invitation, so with spades covered I bid 3♠, and otherwise bid 3♦.
Play with me at your peril!
Luckily you will be discussing this afterwards, so will not have to agonise again.