An opening bid of two spades shows
(a) 8-12 points and
(b) 5/5 in the minors or 5/5 majors or Semi solid major
Response 2NT relay:
Opener rebids 3C=minors 3D=majors 3H/3S=natural
A bidding convention is an agreement between two players on a different meaning of a bid in the card game bridge. These agreements are made so that partners can more quickly determine which contract, with both their cards, they can win together. Often, conventions are forged together into one, which is then called a bidding system.