Shows exactly 3-card support by opener for responder's suit.
Example: 1
- (D) - 1
- (2
) -DOUBLE
Support Doubles are on through the level of 2 of partner's suit.
If opener's RHO doubles rather than overcalls, opener can make a Support Redouble.
Support Doubles and Redoubles are never used after a 2-level response such as 1
- 2.
Other bids:
- 1 - (P) - 1 - (1) - 2
shows 4 hearts.
- Any other natural bid denies 3-card support.