By JIM KAPLAN

Here’s a new convention. It’s easy enough to use and priceless on the rare occasions it’s needed.

Partner opens with one of a suit, and you have a fantastic fit for it with slam possibilities. The problem is that you hold a void. It won’t help to bid 4NT, because partner might have an ace in your void suit that won’t help you. The answer is to bid your void at the five level. This is called Exclusion Roman Key Card Blackwood (you can also play it as simply Exclusion Blackwood). Your bid asks for key cards (aces and trump king) in every suit but your void. Responses begin with the next suit up as follows.

Next suit up: one or four of the key cards (three aces, trump king).

Next suit up after that: zero or three key cards.

Next suit after that: two key cards without trump queen.

Next suit after that: two key cards with the trump queen.

This may sound complicated, so let’s see it in action. A perfect opportunity arrived in an OK Bridge game I was playing with my friend Paul Laliberte. South was dealing, with East-West vulnerable:

NORTH (Me)
♠Q 6 3 2
♥A K 9 8 7 6 5
♦A K
♣—

WEST                    EAST
♠ 9 7                       ♠8 4
♥ 10 2                    ♥Q J 4
♦ Q J 6                   ♦9 5 3
♣ A 9 7 4 3 2         ♣K J 10 8 5

SOUTH (Paul)
♠A K J 10 5
♥3
♦10 8 7 4 2
♣ Q 6

The bidding proceeded as follows:

South     West     North     East
1♠          Pass      5 ♣•       Pass
5♠ ••      Pass      7 ♠        All Pass

• Exclusion Roman Key Card Blackwood shows void and asks for key cards in any suit but clubs.
•• Shows two key cards without spade queen.

Opening lead: ♣A.

After I bid 5♣, Paul’s choice of available responses were:

• 5♦: one or four key cards.
• 5♥: zero or three key cards.
• 5♠: two key cards without the spade queen.
• 5NT: two key cards with the spade queen.

Knowing South held the spade ace-king since I held the other relevant key cards, I confidently bid 7♠. After ruffing the opening lead, declarer should cash the heart ace and ruff a low heart with an honor to set up the suit. When hearts break 3-2, declarer draws two rounds of spades, ending on the board, and claims. With hearts set to run, dummy holds nothing but winners.

Only about a fifth of all declarers bid the grand slam. That’s understandable. Not everyone would open Paul’s 1♠ , although it qualifies under the Rule of 22 that we use in the first or second suit to initiate the bidding. Add your total high-card points to the length of your two longest suits to your quick tricks: 10 HCP + 10 spades and diamonds + 2 spade winners = 22 in this case. And without ERKCB, North-South will be put to the test. It’s possible to imagine how the others bid:

South     West     North     East
1♠          Pass     4NT        Pass
5♥ •        Pass    6 ♠          All Pass

• Two key cards, but one of them may be the club ace.

Our knowledge of ERKCB enabled Paul and me to bid a grand slam with just 26 HCP and finish first in our division for the maximum 1.50 masterpoints.