In contract bridge, various bidding systems have been devised to enable partners to describe their hands to each other so that they may reach the optimum contract. A key initial part of this process is that players evaluate their hands; this evaluation is subject to amendment after each round of bidding. Several methods have been devised to evaluate hands taking account of some or all of strength, shape, fit and "quality" of a suit or the whole hand. This article explains the methods and the situations in which each may best be used.