LEBENSOHL

When partner opens 1NT and RHO bids a suit you may just want to play in a 6 card minor at the 3 level. The only problem is that if you bid 3 of a minor directly it is FORCING. So what's to do? The secret is to use 2NT as an intermediate bid (sometimes known as a "puppet"). This warns partner you have no interest in game. Partner MUST first bid 3C (like a transfer) which you can then either pass or CORRECT to your suit. Partner should then Pass.
This is the basis of the LEBENSOHL convention. It is a system for dealing with intervention after 1NT when you have no interest in Game. It follows then that you can use direct 3 level bids to force partner to bid on.
This is only part of the system, but you should be aware of it as it is very common in club bridge. It also has other uses which are far more complex and should only be used in a practised partnership!
There are also other situations where 2NT no longer has its normal meaning. This is because in competitive auctions, 2NT is rarely a useful bid, as the key is usually to locate a sensible suit fit, and if you have a 2NT (10 - 12 balanced) hand you should probably be doubling for penalties. For instance, after a weak 2 opening, there is a difference between
2S (weak) - X - Pass - 3H

and

2S (weak) - X - Pass - 2NT
Pass - 3C  -  Pass - 3H

The second sequence shows no interest in Game (0 - 8), while the first is a decent (ish) hand and suit. The reason is that the Weak 2 has deprived your side of bidding space. If the opening bids had been 1S - X - Pass, you have room to show a good hand (9+) by jumping to 3? and bidding 2? with anything else (0-8).
This kind of differentiation makes life much easier for partner to make further, correct, decisions later in the auction. And it is of course our prime duty to keep partner well informed and very happy. We cannot play Bridge alone, so we must communicate accurately if partner is to succeed. For partner's success is also our success.

Enjoy

Kit

BID TO THE SCORE

The vagaries of scoring, I hear you call. What does it mean? How does it work? And why? And why should we worry about it?

Why? Because - nothing else matters! Fits, contracts, slams, part-scores, sacrifices - everything is subject to the SCORE.

We sacrifice when we are Not Vul against Vul, because if we go 3 down doubled we lose 500 against their 600+ Game score This is equivalent to a plus of 100.

If we are Vul against NV and we go 3 down doubled we lose 800 against their 400+ game score. BAAAAD. A minus of 400.

Tactics tactics tactics.

Playing Rubber Bridge you are Game and 60 and you pick up this:

AQX

KJX

AJXX

KXX

There are 2 passes to you. What do you bid? 1D, rebidding 2NT is the classic "book" bid. But look at the score. You only need 40! That's 1NT. So bid it. Yes bid 1NT at that score. At teams or Duplicate it would be a simply terrible bid (because Game might be on), But at Game and 60 it's a great bid. Close out the rubber. Slam is a distant paradise to be ignored at all costs. The bid is determined by the score. Not your hand.

Ax

KJ10xx

AJx

KJx

A Heart is opened on your right. You're playing Duplicate. What do you bid? The book might say 1NT (showing 15 - 17 and a H stop) But how does Vulnerability affect your strategy?  Consider if they are Vul and you are not, then the best you might make is 3NT for 400. However, what if you PASS, and then partner re-opens with a Double? Now if they go 2 off you make 500! Bit of a pipe dream maybe. But it happens. On the other hand swap the Vulnerability and everything else changes as well. Now if you pass and partner doubles, they go 2 off for only 300, whereas you might make 600 in 3NT. The score again determines how you bid; what your strategy might be. Honestly, the only thing that really, really, really matters is - THE SCORE!