In the game of Contract bridge

Contract bridge

Contract bridge, usually known simply as bridge, is a trick-taking card game using a standard deck of 52 playing cards played by four players in two competing partnerships with partners sitting opposite each other around a small table...

 a three suiter (or three-suited hand) denotes a hand containing at least four cards in three of the four suits. As a bridge hand contains thirteen cards, only two hand patterns can be classified as three suiters: 4-4-4-1 and 5-4-4-0.

In natural bidding systems

Bidding system

A bidding system in contract bridge is the set of agreements and understandings assigned to calls and sequences of calls used by a partnership, and includes a full description of the meaning of each treatment and convention...

, strong three suiters are often difficult to describe, as — following the likely response of partner in the short suit — they do not allow for a high-level notrump rebid, nor for a reverse bid. Some systems therefore use dedicated opening bids to describe strong three-suited hands (e.g. the 2 opening in the Roman system).

The standard treatment to describe a three-suited hand after an opposing opening in a suit is the takeout double

Takeout double

In the card game bridge, a takeout double is any call of "double" that shows a desire to compete for the contract by further bidding. Many takeout doubles nearly require partner to bid; partner should pass for penalty with an appropriate hand, but that is uncommon...

. Conventions like the Kantar cuebid and Cansino can be used to introduce a three-suited hand after an opposing 1NT opening.

Links

• http://www.chrisryall.net/bridge/two/clubs-4441.htm offers complete 'Roman' 3 suited system notes, showing the type via 2♣ strong opening .. 2NT rebid