In natural bidding systems most notrump (NT) bids are made with balanced hands and within a narrowly defined high card point (HCP) range. In these systems, such as Acol and Standard American, NT bids are limit bids and therefore are not forcing. Bearing in mind the need to bid only to the optimum contract and no higher, bids above game are made only in specific circumstances, one of which is to alert partner to the fact that a slam may be possible and inviting partner to take part in the decision-making process.