Brown sticker is a category of
contract bridge
Contract bridge, or simply bridge, is a trick-taking card game using a standard 52-card deck. In its basic format, it is played by four players in two competing partnerships, with partners sitting opposite each other around a table. Millions ...
conventional agreements defined by the
World Bridge Federation (WBF).
[The World Bridge Federation (WBF) definition of Brown sticker conventions in it]
Systems Policy manual, page 3
Brown sticker conventions are considered to be difficult to defend against, and thus are permitted only at high levels of tournament play. Only
highly unusual methods (HUMs) have a higher classification.
A convention qualifies for a brown sticker if it fulfills any of the following criteria:
# An opening bid of 2 through 3 may be weak and does not promise a known suit.
# An overcall of a natural opening at the one level does not promise four cards in a known suit.
# A weak two-suited bid where one of the suits by definition may be only three cards or shorter.
# It is used for protection of
psychic bid Psychic bid (also psych, pronounced to rhyme with ''like'') is a bid in contract bridge that grossly misstates the power and/or suit lengths of one's hand. It is used deliberately to deceive the opponents. Normally, the psychic bid is made with a we ...
s, or systemically required psyches.
Notable exceptions are the
Multi 2 diamonds
Multi-coloured 2 diamonds, is a contract bridge convention whereby the opening bid of 2D shows a defined range of hand types. These always include a weak-two bid in a major suit, and the second option, that must be a strong. The inherent ambigui ...
(due to its popularity), a natural 1NT overcall, and
cue bid
In contract bridge, a cue bid (also, cuebid or cue-bid) is either a bid of the opponents' suit, or "slam seeking": a slam-investigating bid made during an auction's later rounds that shows control of a suit.
Traditionally a cue bid is "slam seeki ...
s on strong hands to force partner.
In general, if a bid is weak (or potentially weak having multiple options) and does not promise four cards in a defined suit (when weak), then it is likely to qualify as a brown sticker convention.
References
{{WPCBIndex
Bridge conventions