Fourth Suit Forcing

What is Fourth Suit Forcing?

Fourth Suit Forcing is a way for responder to slow down an awkward constructive auction. In its standard scope, responder first makes a one-over-one response and then bids the remaining suit after opener shows a non-jump, non-reverse second suit. The fourth suit is a forcing question rather than a natural suit.

The call says that responder still needs information. Opener may need to show delayed support, a stopper for notrump, extra length, or simply whether the hand is minimum or stronger.

Forcing level

The forcing level is a partnership choice. Some pairs treat any Fourth Suit Forcing bid as committing the partnership to game. Others allow a lower stop after one more round in specific auctions.

The required strength follows from that choice. In the one-round style the bid shows roughly invitational values or better, around 10 or 11 points and up. In the game-forcing style responder needs roughly opening values, around 12 or 13 points and up.

The game-force style is cleaner for memory. The lighter style creates more room for invitational hands, but it demands sharper follow-up agreements.

• Playing Fourth Suit Forcing as game-forcing makes opener's rebids easier.
• A one-round version needs clear later signoffs; opener must jump with extras to reach game.
• Because the fourth suit carries the strong hands, many pairs play responder's natural jump rebids as merely invitational.
• Passed-hand auctions usually need separate treatment because responder has already limited the hand.

When the fourth suit is natural

A suit is not automatically artificial merely because it is the fourth suit named in the auction. The following are common standard exclusions, although a partnership can adopt different explicit agreements.

• When all four suits are bid at the one level, as in 1 - 1 - 1 - 1, the fourth suit is commonly natural and forcing for one round.
• After opener reverses, the auction is already forcing and responder's bid in the fourth suit is commonly natural.
• In many North American methods, including common 2/1 Game Force structures, Fourth Suit Forcing applies only after a one-over-one response. A later fourth-suit bid after a two-over-one is then natural because the earlier response has already created the force.
• That scope is not universal. In many Acol methods, including the modern EBU framework, the fourth suit remains artificial and forcing after a two-level response. The partnership must agree which treatment applies.
• A jump in the fourth suit is commonly natural rather than Fourth Suit Forcing.
• Competition normally turns Fourth Suit Forcing off, and passed-hand auctions require a separate agreement.

Opener's priorities

Opener should not assume responder actually holds the fourth suit. The usual job is to choose the most useful descriptive rebid; the exact priority order varies by partnership, so the list below is a common guide rather than a fixed rule.

• Show three-card support for responder's major when available.
• Bid notrump with a stopper in the fourth suit and a suitable hand.
• Raise the fourth suit only when the partnership explicitly uses that call to show four cards.
• Rebid a long suit when no better descriptive call exists.
• Jump or take a strong action with extra values.

Responder's continuations

After opener answers, responder's bids are natural. In the game-forcing style every call below game is forcing, so responder can describe the hand in comfort: raising one of opener's suits, rebidding the long suit, or bidding notrump once opener has denied a stopper problem.

In the one-round style, responder's minimum continuations, such as a simple preference or a repeat of the long suit, are invitational and opener may pass. Anything stronger from responder keeps the auction alive.

Example auctions

Fourth Suit Forcing is a tool for auctions that are not ready to be placed. It gives responder one forcing bid that asks opener to resolve the missing information.

Responder hand examples

Responder uses Fourth Suit Forcing when there is enough strength to keep bidding but no clear final contract yet.

Common mistakes

FAQ

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