About Strong Preemptive Competitive Conventions
We have covered opening 1 of a major bids (5+ card suit) with our new bidding conventions nonForcingNT, Extensile2♣, GameForce2♦ and Two Face 2♥, Compressed Bergen and others.
For minor suit opening bids we have covered the requirements for ToucanClub and Macaw (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 hand 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 a 1 and 1/2 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 artifical 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 the oppoents 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 like difficult for opponents. For Modern American, we prefer interfering where possible with transfer bids. We define conventions called TRASH (Transfer and Shape), TRAP (transfer and penalize) and Transfer Advances, TransferOverForcingNT, etc.