Efos/Extended Stayman

Efos is an acronym for Economical Forcing System, which is used in international championships. The Extended Stayman convention is a feature of this bidding system. This convention allows a partnership to find 4-4 and 5-3 Major fits, as well as Minor suit fits. Efos/Extended Stayman may be used to search for Major and Minor suit fits after a strong No Trump opening. The responder bids 2 Clubs to ask about the distribution of the opener's hand, and the opener responds as follows:

Opener		Responder		Meaning
1 NT		2		Efos/Extended Stayman
2				No 4-card Major suit and minimum opening, 15-16HCPs
2				A 4-card Heart suit and 15-18HCPs
2				A 4-card Spades suit and 15-18HCPs
2 NT				Both 4-card Major suits and minimum, 15-16HCPs
3				No 4-card Major suit and maximum, 17-18HCPs
3				Distribution 2-2 in both Major suits and maximum, 17-18HCPs
3				A 5-card Heart suit, 17-18HCPs, and 2-card Spade suit
3				A 5-card Spade suit, 17-18HCPs, and 2-card Heart suit
3 NT				4-4 distribution in both Major suits and 17-18 HCPs

If the first rebid by the opener is a 2 Diamonds rebid, showing no 4-card Major suit and minimum opening, then the responder can ask whether the opener has a 3-card Major suit in the following manner:

Opener		Responder		Meaning
1 NT		2		Efos/Extended Stayman
2				No 4-card Major suit and minimum opening, 15-16HCPs
		3		Asking for a 3-card Major suit
3				No 3-card Major suit
3				A 3-card Heart suit
3				A 3-card Spade suit
3 NT				3-card suit in both Major suits

If the first rebid by the opener is a 3 Diamonds rebid, showing a distribution 2-2 in both Major suits and maximum, 17-18HCPs, then the responder can ask about the distribution of the Minor suit holding of the opener in the following manner:

Opener		Responder		Meaning
1 NT		2		Efos/Extended Stayman
3				Distribution 2-2 in both Major suits and maximum, 17-18HCPs
		4		Asking for best Minor suit after opener shows 2-2 distribution in both Major suits
Pass				Promises a 5-card Club suit and minimum values
4				Promises a 5-card Diamond suit and minimum values
5				Promises a 5-card Club suit and maximim values
5				Promises a 5-card Diamond suit and maximim values

Efos/Extended Stayman is a convention, which assists the partnership to determine Major and Minor suit fits. It must be entered on the Convention Card and explained to any opponent who wishes an explanation.

If you wish to include this feature, or any other feature, of the game of bridge in your partnership agreement, then please make certain that the concept is understood by both partners. Be aware whether or not the feature is alertable or not and whether an announcement should or must be made. Check with the governing body and/or the bridge district and/or the bridge unit prior to the game to establish the guidelines applied. Please include the particular feature on your convention card in order that your opponents are also aware of this feature during the bidding process, since this information must be made known to them according to the Laws of Duplicate Contract Bridge. We do not always include the procedure regarding Alerts and/or Announcements, since these regulations are changed and revised during time by the governing body. It is our intention only to present the information as concisely and as accurately as possible.