2
; 2NT
Opener has a strong balanced hand of 17-22 hcp or a powerhouse balanced hand of 25+ hcp. There is no upper limit to opener's strength, and the means by which opener shows extra strength is discussed below under Opener's Strategy.
Responder has a 4-card or longer club suit and either 8-11 hcp or 14+ hcp, and denies a 4-card major suit.
The auction is game-forcing.
Opener assumes that responder has 8-11 hcp.
If opener has any hand within the range of 17-22 hcp,
there is an absolute partnership maximum of 33 hcp
and it therefore not worth advancing towards slam.
Only perhaps with an absolute maximum of 21-22 hcp and a good club fit
opener might invite slam with a natural bid of 4
after responder signs off in 3NT (we can play in 4NT if the invitation is refused).
If responder has the higher range of 14+ hcp, it is responder's responsibility for making a further try towards slam.
If opener has a powerhouse hand of 25+ hcp then, on the next round, he must ensure that a slam is reached by bidding 5NT, 6NT or 7NT. He bids 6NT with 25-26 hcp, 7NT with 29+ hcp, and 5NT (to invite a grand slam) with 27-28 hcp. These bids will happen very rarely, but responder cannot fail to recognise an unexpected natural high NT bid as showing the 25+ hcp balanced powerhouse.
Responder has denied a 4-card major but he should be aware that opener may have a 5-card major. With most hands having 3 cards in one or both majors, responder should look for a 5-3 major suit fit. The bids available to responder assist that, while giving opener the information he needs to determine whether 3NT will be a playable contract or not.
If responder has the higher range of 14+ hcp, our side has at least slam-invitational values. Responder must not allow the bidding to stop at game. He must make a further try towards slam by bidding beyond game. Opener will recognise this as showing 14+ hcp.
You can refer to these worked examples, Opener Balanced — Responder Raises Clubs, to see how these bids work in practice.

(obviously not natural)
to allow responder to bid major suit stoppers.
Otherwise opener should bid 3NT if having no worries, or try for a club contract.

/
bid by opener
to 5
.
The remaining bids cover responder's action when he has the 14+ hcp higher range. They can occur immediately, but may also be used on the next round of the auction after responder has explored for some kind of suit fit. They are natural bids, and have the same meaning in any case.
Author: Chris Burton
Gravesend Bridge Club