Which defence do you play to the 1NT opening and why?

[Zelandakh]

X for H+m

2C for S+m

See my strong NT defence for a slightly more sophisticated version based on the idea of X = ♥ + another and 2♣ = ♠ + another.

[gwnn]

I like the defence Helene mentioned against 15-17 as well. Not sure about 13-15 or weaker.

[gwnn]

If I have a nice 13, I'll think, OK, I'll have the top end of my 11-13 range (for 1NT rebid or equivalent), but partner will be able to manage that just fine - so I don't upgrade.

Upgrading into 1NT has a lot of advantages other than constructive auctions, such as making defence more difficult and preempting opponents and/or talking them out of game. I'm pretty sure you know this though so I'm not sure why you don't mention it in your post.

[Charlie Yu]

See my strong NT defence for a slightly more sophisticated version based on the idea of X = ♥ + another and 2♣ = ♠ + another.

I read your version. One question, how does one respond to 2C for D+H+S/spade+longer H/m? Can responder pass your 2C bid?

[Zelandakh]

I read your version. One question, how does one respond to 2C for D+H+S/spade+longer H/m? Can responder pass your 2C bid?

It is all done with P/C bids. Responder could potentially pass with long clubs if they thought it likely to be the best spot but it is not going to be a common auction. Over a weak NT this protected by being limited (no X) and over a strong NT it is protected by the low probability of game. I suppose in theory it would be possible to miss 6♣ with Overcaller holding a great hand with 4♠-5♣ after a psyche from Opener but I would not advise playing for that. :lol: