ACES ON BRIDGE
When you lead a top club against four spades, partner’s two is a grave disappointment. In order to set four spades, it appears to be necessary to win a trick in diamonds. It looks correct, therefore, to shift to a diamond.
However, even if declarer’s distribution is 5=3=3=2, four spades cannot be set; declarer can arrange to pitch a diamond on dummy’s clubs. But if South’s distribution is 5=2=4=2, it might be possible to defeat the contract; can you see how? One possibility is to lead a diamond, playing partner for the jack. Then the defense can win a diamond before declarer discards two diamonds on dummy’s clubs. However, the diamond shift is disastrous if declarer holds the K-J-x-x of diamonds.
There is a better way to set four spades without risking a diamond lead away from the queen.
You should continue with the club ace and a third club, which dummy will win with the jack, declarer pitching a diamond.
Declarer leads a spade to his king and your ace. You then lead a fourth round of clubs, which partner ruffs low and declarer overruffs. South has lost his second discard and is later forced to take a diamond finesse. When that loses, four spades is down one.
As you can see, if West fails to play the ace, king and another club, and later a fourth club for East to ruff, then declarer will eventually be able to pitch two diamonds on dummy’s clubs.
ANSWER:
The two-diamond call is typically not based on spade support (although it may be a prelude to a jump in spades with four-card support). You are asked to define your hand better, and your choice is to raise clubs — which would be forcing — or to bid no-trump. I prefer the former; slam in clubs may be excellent, and your support is far too good to conceal. Even a jump to four clubs may be in order.