This is an offensive bid that shows the unbid suits,
rather like a takeout double by the defenders. Double of a major usually
promises at least 4 of the unbid 2nd major and at least tolerance for the unbid
minors. Some play that a double after a minor shows 4 of both majors. The direct bid of a major after opps bid
the other one therefore shows 5 or more in the suit. A partnership therefore may distinguish between 4 and 5+ card suits.
The number of points required to make a negative double vary, but the most common standard is 8 HCP (or a very good 7 HCP).
S: xx
H: Ax
D: xxxxx
C: KTxx
S: Qxxx S: x
H: J10xx H: KQxx
D: JTxx D: AKQx
C: Ax C: Qxx
S: AJTxxx
H: xxx
D: x
C: QJ
W N E S
P 1C 1S
X P 2H 2S
3H P/O