Opening Strong Hands and Competitive Bidding Conventions
We have covered opening 1 of a major bid (5+ card suit) with our new bidding conventions: NonforcingNT, Extensile2♣, GameForce2♦ and Dual-Range 2♥, Compressed Bergen, and others.
For minor suit opening bids, we have covered the requirements for Taco Club and Unbalanced Diamond.
This section covers bidding Strong, Preemptive and Competitive hands.
With Modern American, we use the opening 1NT bid to show balanced 15-17 HCP hands. These are the hands too strong to open 1♣ when balanced.
With a bit more than 1NT in values, but still balanced, we use the opening bid of 2♣ to show 18-19 HCP balanced. Think of this bid as a 1½ NT. With 20 or 21 HCP and balanced, we open 2NT. That means we have a single bid to show all balanced hands (without a 5-card major) regardless of their high card points
That means we use the artificial bid of 2♦ to show all hands with more than 21 HCP. We also use the 2♦ opening bid for unbalanced very strong hands. These hands may not have 22 HCP in strength, but with shape valuation will play that strongly. This opening bid is forcing, and you are so strong you want to continue bidding even when partner has less than 6 points.
Competitive bidding is the most common auction in bridge. Rarely is it beneficial to your results to sit back and allow the opponents to bid their auction easily and without interference.
Several opponents' bids call for more frequent interference than others. The first is to interfere with their opening 1NT bid. Make it difficult for opponents. In Modern American, we prefer interfering with transfer bids where possible. We define conventions called TRASH (Transfer and Shape), TRAP (transfer and penalize) and Transfer Advances, TransferOverForcingNT, etc.