microcap, on 2012-June-04, 10:14, said:
It has to be a pretty good rule not to bid notrump with a void in partner's first bid natural suit...comments?
If you mean that you should never bid notrumps at any stage in the auction, that's obviously an awful rule. If it went
1♣-(1♦)-1♥
1♠-2♦
3♣
presumably you'd be happy for responder to bid 3NT with a 3550 13-count.
On the first round of the auction, a natural notrump bid should show a balanced hand, because with an unbalanced hand you should be showing your suits. As you exchange information about shape, bidding notrumps becomes less descriptive of a balanced hand, and more of a strain suggestion in the context of what has been shown already.
That applies to this sequence, given your methods. Responder already knows a lot about opener's shape, so bidding notrumps just says "Given what you've shown, I think notrumps is likely to be our best strain." As opener has promised five clubs, responder will give preference to clubs on almost all hands with three of them, and some hands with two. Hence 1NT will often have short clubs, though 1 or 2 is more likely than 0.
The main reasons for passing 1
♠ on this responding hand are that game is unlikely, 1
♠ is likely to make, and bidding again may get you too high. However, if you add some high cards to the responding hand without changing the shape, at some point it will become worth 1NT because of the possibility of game. Kxx KJ10xx QJ10xx -, for example, is too good to pass 1
♠, so what can you bid but 1NT?