The 2-over-1 bidding system, all the rage these days, deserves our consideration.

When player A opens with a one-bid, there’s no interference and player B responds with two of a lower suit, it’s a game-forcing auction. These are 2-over-1 replies:

1 ♠           Pass           2 ♥
1 ♠           Pass           2 ♦
1 ♠           Pass           2 ♣
1 ♥           Pass           2 ♦
1 ♥           Pass           2 ♣
1 ♦           Pass           2 ♣

(Some play last 2 ♣ is not game-forcing.) A jump-shift response in a higher suit like 1 ♥ -Pass-2 ♠ typically shows a six-card suit and no more than four high-card points.

The advantage of the 2-over-1 system is twofold. First, there’s no chance that the bidding will subside short of game. Second, with a big hand and slam aspirations, you can bid slowly and gain enough information to decide.

With an opening hand and nothing more, bid quickly to game unless partner jumps. Say you hold:

♠A 10 4
♥K Q 9 4
♦K 5 4 3
♣ 5 4

Partner               You
1♠                       2 ♦
3 ♦                      4 ♠

Here you’re bidding slowly with a big hand:

♠A 10 4
♥A K Q 4
♦K Q 4 3
♣ 4 3

Partner               You
1♠                       2 ♦
3 ♦                      3 ♠ 
4 ♣                     4NT etc.

What do you bid with 10 or 11 HCP — the kind of hand you used to reply with two of another suit? Enter the 1NT forcing convention that’s part of 2-over-1 theory. When partner opens 1 ♥ or 1 ♠ , a reply of 1NT by an unpassed hand is forcing for one round. Showing 6-12 HCP, this 1NT keeps the auction alive and allows you to clarify your holding with your next bid.

♠Q J 4
♥A 10 6 5
♦K 10 6 5
♣ 3 2

OPENER               YOU
1♠                           1NT
2♦                           3 ♠ !•

• Natural and invitational

You don’t immediately bid 3♠ , because that would have shown a four-card suit. At other times responder will rebid a six-card suit when there’s no fit for opener’s bid suits:

♠J
♥Q J 10 7 5 3
♦A 5 4
♣ 4 3 2

Partner                You
1♠                        1NT
2♣                        2 ♥

The 2-over-1 system isn’t perfect. At times opener must rebid a three-card minor:

♠A K J 3 2
♥A 4 3
♦6 5
♣ 4 3 2

Opener                Responder
1♠                        1NT
2♣

There’s also no hope for a 1NT contract in response to a major-suit opening bid unless the 1NT bidder previously passed. That said, 2-over-1 can be pure joy. Here’s a deal that arose during a teaching session. North is dealing, with both sides vulnerable:

NORTH
♠J 3
♥A J 10 8 4
♦A Q
♣A K 5 3

WEST               EAST
♠ 10 9 5 2          ♠K 8 7 4
♥ K 6 5              ♥Q 9 3 2
♦ 7 6 5               ♦4 3
♣ J 10 6             ♣9 8 7

SOUTH
♠A Q 6
♥7
♦K J 10 9 8 2
♣ Q 4 2

The bidding proceeded as follows:

North        East        South        West
1♥             Pass        2 ♦            Pass
3♣             Pass        3 ♦            Pass
4♦              Pass       4 ♠•           Pass
4NT           Pass       5♥ ••         Pass
6♦              All Pass

• Shows first-round control
•• Shows two of the five key cards (four aces, diamond king) without diamond queen

Opening lead: ♠10

As soon as North learns that South has an opening hand, slam is in the air. That’s why North deliberately bids 4♦ rather than 5 ♦ over South’s 3 ♦ : he’s asking for more information. When South shows the spade ace, we’re off to the races. Against any lead slam makes with an overtrick.