Quote Frances Hinden
"For the long diamond to be important for a club discard, declarer's shape is 2632, or 3532. That's consistent with the auction, but there's no reason for him to have played a spade at trick two with that: he could just play diamonds himself (before or after some trumps depending on his trump holding).
If we trust that declarer is doing something reasonable (dubious of course, but we have to start somewhere) then it's not a tempo hand, because he's deliberately given up a tempo. I can't construct a hand where we need to attack clubs at once."
Why can't declarer's shape be 2533? I would class the opps to be average club players and playing a spade for a ruff looks reasonable at this stage. Declarer would not know that diamonds will break 3-3 and with 3 small clubs would not know that they lie badly.
Quote J Silver
"At this vulnerability, I doubt partner would let 4♥ play if he had 4♠. More likely, he has 2. In that case, declarer will need some ruffs in dummy, and it sure looks like he's trying to get some. I'd lead a ♥. This will put him in a bind if partner has the K. I don't think a ♣ lead is urgent or even advisable. If declarer wanted to set up the 4th ♦, he would've ducked the first trick or played another ♦ himself."
Your overcall is ostensibly weak but at this vulnerability after partner has passed could be undisciplined. I would guess that partner's raise must be with at least 3 and suggests some defence against 4H.
It would seem reasonable to put partner with either 2623 2524 or 2533 shape. I can't see a diamond lead having any advantage over a club lead with any of these distributions, whereas it could be essential to lead a club to break the contract if declarer is 2533 shape. So the question moves on to what does partner need in clubs. If partner has K109 you have 2 club tricks if you lead the jack. If partner has K10x you need to lead small from J6. .....................Oh it has just occurred to me that if you grab 2 club tricks they are set up, so with trumps 3-2 they can provide discards to make 10 tricks. So perhaps it doesn't matter what you lead back.
This was the actual deal and I was sitting north. Partner played a 2nd diamond and after trumps were drawn, one losing club was discarded on the established diamond. When the contract was made I perhaps unjustifiably berated partner for not switching to a club.
Onto the bidding. I am never sure in these circumstances whether or not I should compete to the 3-level in spades, thereby possibly pushing opponents into the heart game which they otherwise might not have bid. On the other hand you could argue that if 4H makes they would have bid it anyway. Should you compete to 3S only if you have good defence to 4H? Views on this gratefully received.