Source: ACBL
[ilink url=»http://csbnews.org/?p=59818″]Access to Part I[/ilink]
There are lots of cuebids in today’s game — control, support, stopper, and Western, to name some. Against these cuebids and the majority of artificial bids, double is best played as lead directing, but there are debatable cases and some logical exceptions.
To take a debatable case, suppose that you are East and the bidding is:
| West | North | East | South |
1 |
1 |
1 |
|
| Pass | 2 |
Dbl | |
East’s double could be the mirror variety — the opponent stole my 2 call — or it could be lead-directing, or it could be «undouble.» The mirror double is sensible because East could hold a hand like:
AJ4 KQ10974 
KJ3 7.
He is happy to emphasize his extra length and values with no risk; he isn’t declaring.
A lead-directing double doesn’t make sense because partner will normally lead a heart making double redundant.
What makes better sense is the undouble treatment, warning partner against a heart lead and suggesting that he look elsewhere, perhaps a hand resembling:
J73 J97643 AKQ4 –
If they play a spade contract, East welcomes either a club or diamond lead. In any case, be prepared and define this double, preferably either mirror or undouble. One artificial bid, the splinter, is a clear exception to the double as a lead-directing treatment. Suppose you are East in this auction:
| West | North | East | South |
| 1 |
|||
| Pass | 4* |
||
(*) Spade raise, diamond shortness.
Assume you are West, and the auction is:
| West | North | East | South |
| 1 |
|||
| Pass | 2NT* | Pass | 3** |
(*) Jacoby 2NT. (**) Club shortness.
In the first sequence, is it useful to double and have partner lead a diamond? How often will the defense gain an advantage by leading dummy’s diamond singleton or void against a spade contract?
In the second example, is it useful to double to tell yourself to lead declarer’s short suit, because you almost surely will be on opening lead?
Because the answer to these questions is a resounding «no,» double should take on a different meaning versus shortness. With the opponents in a game force, it is unlikely that your side can make a high contract. You might well have a profitable sacrifice, however, and double should show a long suit to serve as trumps.
As with most trump suits, strength is not as important as length — a six-card suit headed by the queen will suffice if partner saves with, say, K–x–x–x in support. Because we are considering a sacrifice, vulnerability is all important.
Obviously, the best condition to save is when you are non-vulnerable versus vulnerable — down three is a good result against a game. Equal vulnerability is less tempting — down two is worthwhile — and vulnerable versus non-vulnerable, it is hardly ever right to save. At these unfavorable colors (red vs. white), your «save» should be bid to make, so that down one, at worst, is still a good result.
These calculations change if the opponents can make a slam, but a cheap sacrifice is a viable objective, so double of a splinter is best played as sacrifice-oriented, typically showing at least a six-card suit and some side suit shortness to limit the losers.
It is important not to hold surprise defense, such as Q–J-10–x in their trump suit. Partner, void in their trump suit, will strain to sacrifice with support. This is the last thing you want partner to do; the sacrifice is apt to lead to the dreaded phantom save — your side goes minus, while their contract would be set due to the bad trump split.
Return to the Jacoby 2NT auction: If you hold long clubs and a sacrifice-oriented hand, double will send that message.
The other sequence has a different wrinkle because partner will almost surely be on lead if they buy the contract. At three-quarters of the vulnerabilities, retain the double to suggest a diamond save (re-sponder’s short suit). What if they’re not vulnerable and you are? You could use the same agreement for simplicity, but an adjustment is probably an improvement.
For instance, let the double of 4, suggest a lead, not a sacrifice, but the lead is not dia-monds, the short suit. Instead, try the lowest under-ranking suit, clubs in this case. The logic is that East could bid 4, albeit at some risk, if he was dying for a heart lead, but he’d have to increase the level to show clubs (5).