The Herbert Negative is used in response to an ACOL Two Bid
. The cheapest step response by responder is artificial, showing 0-7 points without support for opener's suit. Examples:
Opener's rebids are natural.
The benefit of the Herbert Negative is that it saves bidding space. The traditional negative response is 2NT, which consumes more space and "wrong-sides" the play of the hand in no-trumps.
The drawback to the Herbert Negative is that it takes away the natural, positive meaning of the cheapest suit response. To bid the suit naturally, responder must make a jump-bid at the 3-level instead.