LAW 40 - PARTNERSHIP UNDERSTANDINGS

1. Players' Systemic Agreements
   1. 1. Partnership understandings as to the methods adopted by a partnership may be reached explicitly in discussion or implicitly through mutual experience or awareness of the players.
      2. Each partnership has a duty to make its partnership understandings available to its opponents. The Regulating Authority specifies the manner in which this is done.
   2. Information conveyed to partner through such understandings must arise from the calls, plays and conditions of the current deal. Each player is entitled to take into account the legal auction and, subject to any exclusions in these laws, the cards he has seen. He is entitled to use information specified elsewhere in these laws to be authorized. (See Law 73C.)
   3. A player may make any call or play without prior announcement provided that such call or play is not based on an undisclosed partnership understanding (see Law 40C1).
   4. The agreed meaning of a call or play shall not alter by reference to the member of the partnership by whom it is made (this requirement does not restrict style and judgment, only method).
2. Special Partnership Understandings
   1. 1. An agreement between partners, whether explicit or implicit, is a partnership understanding.
      2. In its discretion, the Regulating Authority may designate certain partnership understandings as 'special partnership understandings'. A special partnership understanding is one whose meaning, in the opinion of the Regulating Authority, may not be readily understood and anticipated by a significant number of players in the tournament.
      3. Unless the Regulating Authority decides otherwise, any call that has an artificial meaning constitutes a special partnership understanding.
   2. 1. The Regulating Authority:
         1. is empowered without restriction to allow, disallow, or allow conditionally, any special partnership understanding.
         2. may prescribe a System Card, with or without supplementary sheets, for the prior listing of a partnership's understandings, and regulate its use.
         3. may prescribe alerting procedures and/or other methods of disclosure of a partnership's methods.
         4. may disallow prior agreement by a partnership to vary its understandings during the auction or play following an irregularity committed by the opponents.
         5. may restrict the use of psychic artificial calls.
      2. Unless the Regulating Authority provides otherwise a player may not consult his own system card between the commencement of the auction period and the end of play, except that players of the declaring side (only) may consult their own system card during the Clarification Period.
      3. Unless the Regulating Authority provides otherwise a player may consult his opponent's system card:
         1. prior to the commencement of the auction,
         2. during the Clarification Period,
         3. during the auction and during the play but only at his turn to call or play, and
         4. following an opponent's request for an explanation, pursuant to Law 20F, for the purpose of correctly explaining the significance of his partner's call or play.
      4. Unless the Regulating Authority provides otherwise a player is not entitled to any aids to his memory, calculation or technique during the auction period and play.
   3. 1. A side that is damaged as a consequence of its opponents' failure to provide disclosure of the meaning of a call or play, as these laws require, is entitled to rectification through the award of an adjusted score.
      2. Repeated violations of requirements to disclose partnership understandings may be penalized.
   4. When a side is damaged by an opponent's use of a special partnership understanding that does not comply with the regulations governing the tournament the score shall be adjusted. A side in breach of those regulations may be subject to a procedural penalty.
   5. 1. When explaining the significance of partner's call or play in reply to an opponent's enquiry (see Law 20) a player shall disclose all special information conveyed to him through partnership agreement or partnership experience but he need not disclose inferences drawn from his knowledge and experience of matters generally known to bridge players.
      2. The Director adjusts the score if information not given in an explanation is crucial for an opponent's choice of action and the opponent is thereby damaged.
3. Deviation from System and Psychic Action
   1. A player may deviate from his side's announced understandings, provided that his partner has no more reason than the opponents to be aware of the deviation [but see B2(a)(v) above]. Repeated deviations lead to implicit understandings which then form part of the partnership's methods and must be disclosed in accordance with the regulations governing disclosure of system. If the Director judges there is undisclosed knowledge that has damaged the opponents, he shall adjust the score and may assess a procedural penalty.
   2. Other than in C1 above, no player is obliged to disclose to the opponents that he has deviated from his announced methods.