Kabel 3NT

Kabel 3NT is an artificial opening bid that asks partner to show specific aces. It’s meant to be used with a strong one-suited hand that will bid a slam if partner has the perfect controls.

A typical Kabel 3NT opener has:

1. A long running suit
2. Only 1-3 losers (frequently 2)
3. A void that makes it impractical to use another slam-sniffing convention like Blackwood

Take the following hand as an example.

—
A K Q 8 7 6 5 2
K Q
K Q J

You are too strong to open 4 — partner will pass with a lone minor-suit ace. A strong 2 opening could be problematic too, because the opponents might preempt cheaply in spades.

A Kabel 3NT opening can curtail these risks while pinpointing the minor-suit ace(s) necessary for a heart slam. The tradeoff is that you can no longer open a gambling 3NT or any other hand type which might occur more frequently.

Several variations of 3NT responses exist. The following structure is from Ron Klinger’s "Bridge Conventions, Defenses and Countermeasures". ¹

Response	Meaning
4	No aces
4	A
4	A
4	A
4NT	Any two non-touching aces. Opener will often be able to deduce what these are.
5	A
5	A and A
5	A and A
5	A and A
5NT	Any three aces
6	A and A

With this scheme, you must be careful which hands to open 3NT. The spade suit affords the greatest liberty, as can be seen here:

K Q J 8 7 6 5 2
—
K Q
A Q J

You are safe to open 3NT and sign off in 4 if partner shows zero aces. If instead partner miraculously bids something like 4NT to show two non-touching aces, even better. (Those aces can only be the A and A.) You can bid 5NT next to probe for the K — more on this later.

However, change the hand slightly to:

—
K Q J 8 7 6 5 2
K Q
A Q J

Now 3NT is a dubious opening. Partner might respond 4 to show the A, which would force you to sign off in 5 holding three losers. This will be the first and last time that partner agrees to play Kabel.

The Kabel responses are not easy to remember — especially for a convention that might come up once in a blue moon. So partnerships must decide whether the extra cognitive load is worth the effort.

Any suit rebid by opener is a natural sign-off. Otherwise, opener can inquire about specific kings by bidding 4NT or 5NT, whichever is cheapest.

If responder has bid 4 of a suit, then opener’s rebid of 4NT asks for specific kings. The responses below are again from Klinger.²

Response	Meaning
5	No kings
5	K
5	K
5	K
5NT	Two non-touching kings
6	K
6	K and K
6	K and K
6	K and K
6NT	Both minor-suit kings
7	Any three kings

If responder has bid 4NT or 5 of a suit, then opener’s rebid of 5NT asks for specific kings. Again, these responses come from Klinger.³

Response	Meaning
6	No kings
6	K
6	K
6	K
6NT	K
7	Any two kings

		West			East
		A K Q 10 7 6 5 4			3
		—			A Q 8 6 5
		K 5			J 3 2
		A Q J 10			9 8 7 6
		West 3NT 4			East 4 Pass

West opens 3NT with a keen interest in finding the A and K. Unfortunately East has the wrong red ace, so West stops in 4.

		West			East
		—			9 7 5 4
		A K Q 8 5 4 3 2			7
		A K			J 9 7 6 5
		Q J 10			A 6 3
		West 3NT 5NT 6			East 5 6 Pass

West uses Kabel to try locating the missing club honors. East bids 5 to show the A, but rebids 6 to show zero kings. West settles for the small slam.

The full deal:

		North
		AQT632
		T9
West		QT8		East
—		98		9754
AKQ85432				7
AK		South		J9765
QJT		KJ8		A63
		J6
		432
		K7542

As mentioned earlier, opening 2 with a hand like West's can spell trouble. North could easily butt in with 2 and get raised by South. Thereafter West would find it quite difficult to navigate a course to 6.

What should you do when the opponents intervene over 3NT? The literature is scant. One strategy is to simply play systems on. Opener has already promised to withstand any conventional response. Moreover, other gadgets like DOPI and DEPO lack a way of showing specific aces.

Response	Meaning
Pass	Unable to make a conventional response because RHO's interference is too high.
Double	A stolen bid, e.g. doubling with the A after RHO bids 4.
Anything else	A conventional response as described above.

If responder passes, then opener's rebids are natural. If responder makes any other call and the next player passes, then opener's rebids are conventional.

This approach gives up a natural penalty double by responder. However, freak distribution around the table might make it difficult to collect sufficient penalties anyhow.

¹, ², ³ Klinger, Ron. Bridge Conventions, Defences and Countermeasures. London, Weindenfeld & Nicolson, 2017.