to ensure full disclosure — not only of its formal bidding system but also of its habits. For example, if a partnership tends to psych under certain circumstances, it is much better prepared to recognize a psych, and to cope with it, than are its opponents. The game's Laws and Proprieties therefore require disclosure of the partnership's tendency. In duplicate bridge, sponsoring organizations often impose a number of restrictions on psychic bids. For example, psychs of strong artificial opening bids (such as strong two clubs) are not allowed by the American Contract Bridge League (ACBL). In addition, if the partner is perceived to have bid abnormally due to taking account of a psych, then the score may be adjusted. Also, partnership agreements to use a "check bid" or psychic control to verify the psych may either be banned entirely (as by the ACBL) or limited in their usage (as by the World Bridge Federation, which designates them brown sticker conventions). See also Bluff (poker) References Further reading Contract bridge bidding