Compare your decision as East in each of these two auctions. Your 1NT opening shows 15–17.
In auction No. 1, you are the responder to a 1NT opening bid. Your point count tells you how high to bid. Most partnerships use Stayman and Jacoby transfers to help find a major suit fit here.
Your decision in auction No. 2 is similar. Partner has shown a balanced hand and about 12–14 points. You still have slam-going, game-going, invitational, and partscore hands, but your point ranges will be higher because partner’s point range is lower than in auction 1. In some ways, your thinking when choosing a rebid in No. 2 is similar to your thinking when choosing your first response in No. 1. Let’s look at some responding hands to rebid. For all hands shown, you are East in auction No. 2.
♠K Q 9 7 5 2 ♥Q 7 6 ♦7 3 ♣7 2
With 9 total points (two extra for the fifth and sixth spades), there is no game opposite the balanced 12–14 high-card points shown by partner. Opener’s 1NT rebid tends to show balanced distribution, so you should have at least an eight-card spade fit. Sign off in 2♠. Compare this to a standard 2♠ signoff response to a 1NT opening bid.
♠A Q 10 7 5 2 ♥7 6 ♦Q 7 ♣A 4 2
With 12 HCP and two length points, you have a game-going hand. You expect a fit opposite opener’s balanced hand. Sign off in 4♠. Again, you can compare this rebid with a standard 4♠ response that places the contract after a 1NT opening bid.
♠A J 9 7 5 2 ♥J 6 ♦7 3 ♣A 4 2
Your 10 HCP plus two length points gives you invitational strength. How does your partnership show this hand? A reasonable agreement to have is that a jump rebid of responder’s suit is invitational. Jump to 3♠. Partner can pass 3♠ with the bottom of his bid and only two spades, so you should have a six-card suit. This bid is not comparable to responses to
1NT. Jumps to three of a major suit by responder are forcing over a 1NT opening bid but only invitational over opener’s 1NT rebid.
♠K Q 9 7 2 ♥Q J 7 6 ♦6 3 ♣7 2
Again, you wish to sign off in a partscore opposite partner’s balanced 12–14 points. One way to do this is to pass 1NT, but I hope you are considering the possibility of a better spot.
You could have an eight-card spade fit. Remember, your first response of 1♠ guaranteed only four cards. You could have a 4–4 heart fit. Opener cannot afford to rebid 2♥ with a minimum hand. There is an important bidding guideline for a minimum opener after a one level response. Unless opener can raise responder’s
suit, a minimum opener should rebid at or below two of his original suit. When opener’s rebid is higher than two of his first suit, opener has reversed. Opener’s reverse requires more than minimum strength (at least 16 HCP).
That guideline means that it is entirely possible for opener to have four hearts. Can you afford to rebid 2♥ as responder? Usually, a new suit by responder is forcing. However, standard bidding treats auction No. 2 more like auction No. 1 than many players realize.
In No. 1, a new suit by responder would not be forcing. Responder’s new suit bid is not forcing in No. 2 either. (In standard bidding, most new suit bids are not forcing after opener bids 1NT at his first or second turn.) You can make a non-forcing rebid of 2♥. Opener can pass 2♥ or correct
to 2♠, depending on which major he prefers. Your 2♥ rebid promises only four hearts but it definitely shows five spades. Why? With 4–4 in the majors, we bid up the line (hearts first), so your first response would have been 1♥, not 1♠.