Flint

The Flint convention is used by a weak major-suited hand after a 2NT opening. An artificial 3 by responder is a relay to 3. Responder then passes or corrects to 3 with a 5+ card major. This allows the partnership to stop below game when necessary. With greater strength, responder could bid hearts or spades directly instead.

One drawback of Flint is that the weak hand typically declares 3 when holding spades. This allows the defenders to see and attack all of dummy's tenaces.

Opener normally completes the relay by bidding 3. However, he can take special actions with game interest in either major.

Opener's Rebid	Meaning
3	The usual signoff. Responder will pass or correct to 3.
3	A maximum hand with 4+ card support for hearts. Responder should pass with spades or correct to 4.
3NT	A maximum hand with at least 3-3 majors. Responder should correct to the appropriate major. It's worth noting that Amalya Kearse recommends bidding 4 instead to prevent the weak hand from always becoming declarer.1

Responder will usually pass or correct to spades with a weak major-suiter. However, there are additional actions that responder can take to show a minor-suited hand with slam interest.

Responder's Rebid	Meaning
Pass	Natural signoff.
3	A correction from 3 is also a natural signoff.
3NT	A hand with 5+ diamonds and mild slam interest. Responder does not promise either major. Opener is allowed to pass.
4/	Open to partnership discussion. Whereas Kearse indicates these as slam-going bids1, the Encyclopedia of Bridge denotes them as sign-offs.

The following deal was analyzed by Charles Goren for Sports Illustrated in 1966²:

Vul: N-S		North
Dlr: North		AKJ4
		AK63
West		A6		East
Q987		Q84		5
J				Q9
K954		South		JT83
K962		T632		AJT753
		T87542
		Q72
		—

North 2NT 3NT 6

East Pass Pass Pass

South 3 5 6

West Pass Pass All Pass

Opening lead: 2

"The 3 bid was a command to North to bid 3, but North had the exceptional hand that permits a different response. His 3NT bid announced strong four-card support for both majors. Suddenly South's mouse of a hand became a potential lion and he roared into action with an unusual jump—a void-showing bid expressing mild interest in slam. That told North that every card except his Q was pure gold, so North bid 6. South corrected to 6 to gain the advantage of playing a 4-4 fit and to permit possible vital discards from the North hand on the heart suit.

"South capped his optimistic bidding with a fine safety play—and a very necessary one. He ruffed the opening club lead, led the T, and when West covered with the queen he let West hold the trick. This left South in complete control. He could afford to win West's shift to a diamond, ruff a second club and lead his last trump. South's remaining diamonds were discarded as North drew the trumps, and six heart tricks added up to the slam."

¹Kearse, A. (1990). Bridge Conventions Complete. Devyn Press.

²Goren, C. (1966, June 13). The Invasion of Jeremy Flint. Sports Illustrated.

The Flint Convention is named for its inventor, British expert Jeremy Flint (1928-1989).