General Description and Motivation
An opening bid of 2♦ is used for three different types of hand:
- 6♥, 5-10hcp
- 6♠, 5-10hcp
- 20-22hcp, Balanced hand.
After the opening 2♦ Responder assumes that opener holds a preemptive hand, and bids to extend the preempt. If opener does anything unexpected, then a strong balanced hand is held.