parsonsdav, on 2018-January-02, 16:27, said:
The only possibility here is if diamonds split 3-3. You can play diamonds three times, and as long as they don't get two clubs first, you'll make nine tricks. If diamonds don't split 3-3, you won't make it on the club J lead, even if clubs are ideally placed.
Considering the ♦ suit in isolation, declarer doesn't depend on 3-3 ♦s:
- If you lead ♦J for dummy, then you improve your chances slightly.
- If you lead ♦s from hand, then you improve your chances substantially.
- If defenders attack ♦s, then your chances are even better. And if you start with ♣J, defenders might well switch to ♦s.
If declarer leads a small ♦ from dummy and they do break 3-3, there are still psychological complications to consider. e.g. Suppose RHO wins a ♦ trick and switches to a ♣. Declarer sometimes has to guess the distribution e.g.
- If RHO led from ♣Kxx or ♣Qxx, declarer might succeed by rising ♣A to block the suit.
- If RHO led from ♣Kx ♣Qx or ♣KQx, then declarer might fare better by finessing.