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Four-ace Blackwood

As with Gerber you will probably be surprised that I have chosen to classify this convention with a recommendation which is lukewarm at best.  It is, after all, frequently the first (and quite possibly the only) artificial convention taught to beginners.

Having said that, if you are a near beginner you will have to learn it simply because many prospective partners will expect you to play it.

But having learned the convention and agreed to include it in your partnership agreement please don’t rush to use it whenever you have thoughts of a slam.  Even when it appears at some point in the auction it will usually be better to do something else first.

First of all a quick run through how it works following which I shall discuss briefly some of the possible extensions and then explain my reservations.

If either partner bids 4NT after a suit has been agreed then it asks partner to give a count of aces according to the following scale.

5♣     0 or 4

5♦       1

5♥    2

5♠    3

Most partnerships will also play the convention when a jump to 4NT is made following any suit bid, with the last bid suit agreed by implication.

The agreed suit is a minor

It will frequently be incorrect to use this convention when the agreed suit is a minor.

If, for example, the agreed suit is clubs and you get a 5♦ response (1 ace) to 4NT then you will not be able to stop short of 6♣.

Not good if you started with just one ace and there are therefore two missing.

Indeed, when clubs are the agreed suit you will need at least two aces in your hand before using Blackwood, and when diamonds are the agreed suit you will need at least one ace in your hand.

With less than this find another route or another bid.

Asking for kings

Many beginners will follow up their ace-asking enquiry almost automatically with 5NT asking for kings.

This is almost invariably wrong.

The bid of 5NT in itself commits you to a small slam, and so there is no point in such an action unless a grand slam is a possibility. In particular, it must guarantee that all four aces are held.  Partner might even bid the grand slam himself rather than give a count of kings if holding a further unknown source of tricks.

So, following your ace-ask and the response, if you want to be in a small slam but have no interest in a grand slam - just bid it.

But for those occasions on which a grand slam is a realistic possibility two versions of the king-asking convention are given on their own page.

Baling out

Of course, if partner’s response shows two aces missing (and sometimes just one) then you will choose to finish at the five-level.

Usually you will do this by simply bidding the agreed suit at the five-level.

Sometimes though, and particularly when a minor suit has been agreed, you will look for a slam and then wish to finish in a contract of 5NT when the required response is not forthcoming.

An immediate sign-off in 5NT is not possible because it would be a king-ask.

A common ploy is to agree that a bid in a new suit at the five-level by the player who bid 4NT in the first place requests partner to bid 5NT, which might then be left as the final contract.

(It is also possible to give this route some further specific meaning if the 4NT bidder chooses to bid again over 5NT.)

Responding with a void

An extension to the standard set of responses allows responder to show a count of aces together with a void.

This is not a widely known part of the convention in normal club play but it has much to commend it.

However it should be noted that there may well have been a more straightforward way of showing the shortage at some earlier stage in the auction.

As these responses lead to at least the six-level it goes, hopefully without saying, that responder should not make any of these bids if he has any reason to suspect that the combined strength of the two hands might be insufficient.  In particular, the void should be ‘useful’ which in general means that it should not be in a suit which partner has bid naturally.

There are possible variations on the scheme of responses but they will all resemble the following to some extent.

In response to the 4NT Blackwood ace-ask:-

six of a suit below the agreed trump suit promises one ace together with a void in the bid suit.

Two extensions to this idea are:-

six of the trump suit promises one ace together with a void in a higher-ranking suit and clearly a potential interest in a grand slam;

5NT promises two aces and an unspecified void (this idea is borrowed from the RKCB convention).

Some pairs add a further bit of jiggery-pokery over 5NT involving a relay of 6♣ after which it will frequently be possible to locate the void, and by implication the location of the two aces.

Evaluation

So why have I not given my seal of approval to such a powerful and popular convention?

There are three reasons:-

first, you will sometimes need to know which aces partner holds - not just how many.

This can usually be achieved by following a cue-bidding route (at a lower level) rather than an ace-asking route;

secondly, if you need to know about kings as well as aces then you will find yourself at the six-level before you have gathered the required information;

and thirdly there is an inbuilt weakness in the Blackwood approach, and this is that you might find out everything you want to know about the side suits, but you will be left completely in the dark regarding the quality of the agreed trump suit - particularly the presence of the king and/or queen.

A variation on the convention is ‘Roman key-card Blackwood’ (RKCB).

RKCB not only gives a count of aces but also finds out about the king and the queen of the agreed trump suit.  This is invaluable information.

So, if you keep four-ace Blackwood as part of your repertoire it will frequently be better to cue-bid at the four-level before launching into Blackwood.  This will give you the opportunity to locate specific aces and/or second-round controls.

My guidance is that as a partnership you should adopt RKCB in preference to four-ace Blackwood at a relatively early stage.

If the slam depends only on the presence of the trump honours then invoke RKCB.

If the slam depends on side-suit controls then use an alternative approach such as a support bid followed by a series of control-showing cue-bids - you might still get to use RKCB later in the auction.

This page last revised 16th Sep 2020

Context  -  The continuing auction - in the slam zone - Blackwood etc..