CHAPTER V
THE AUCTION 

PART II
IRREGULARITIES IN PROCEDURE

SECTION SIX
CONVENTIONS AND AGREEMENTS

LAW 40 - PARTNERSHIP UNDERSTANDINGS 

A. Right to Choose Call or Play

A player may make any call or play (including an intentionally misleading call - such as a psychic bid - or a call or play that departs from commonly accepted, or previously announced, use of a convention), without prior announcement, provided that such call or play is not based on a partnership understanding.

B. Concealed Partnership Understandings Prohibited

A player may not make a call or play based on a special partnership understanding unless an opposing pair may reasonably be expected to understand its meaning, or unless his side discloses the use of such call or play in accordance with the regulations of the sponsoring organisation.

C. Director's Option

If the Director decides that a side has been damaged through its opponents' failure to explain the full meaning of a call or play, he may award an adjusted score.

D. Regulation of Conventions

The sponsoring organisation may regulate the use of bidding or play conventions. Zonal organisations may, in addition, regulate partnership understandings (even if not conventional) that permit the partnership's initial actions at the one level to be made with a hand of a king or more below average strength; Zonal organisations may delegate this responsibility.

E. Convention Card

1. Right to Prescribe

The sponsoring organisation may prescribe a convention card on which partners are to list their conventions and other agreements, and may establish regulations for its use, including a requirement that both members of a partnership employ the same system (such a regulation must not restrict style and judgement, only method).

2. Referring to Opponents' Convention Card

During the auction and play, any player except dummy may refer to his opponents' convention card at his own turn to call or play, but not to his own .