Photo Andrew Robson with the Queen

Source: http://andrewrobson.logonetwork.co.uk/  (Andrew Robson Bridge Club official site).

Small slams occur about one deal in 15: surprisingly common. Only if you’re worried about the number of Aces should you use Blackwood 4NT, or its modern version Roman Key Card Blackwood (RKCB). Think of Blackwood as a way of avoiding slam, not reaching slam.

Mostly you can bid a slam FAST, without  Ace-asking…

F for Fit

Look for nine – even ten – trumps and you can make slam with many fewer than the 33 points for 6NT.

A for Aces

The partnership need all the aces or all but one. If you might be missing two, use Blackwood (or RKCB).

S for Shortages

Voids (especially) and singletons are hugely powerful when you have a big fit.

T for Two-loser suits
Be cautious when you have a suit with two (or more) quick losers. Even if you have all the other aces and kings, your slam will fail if the opponents can cash an ace-king.

Examples:
You open 1 and partner bids 3 (Inv). With which of these hands should you go for slam? 

(A). No. Just one ace, a two-loser heart suit, and no shortage. Settle for 4.

(B). No. Poor shape (5332), and a two-loser club suit. Bid 4

(C). Yes. Excellent shape (5431), no two-loser suit, and a singleton. Bid 6.