You start with the diamond five, to the ten, king, and ace.  South cashes a high club (nine from partner), crosses to dummy with a spade (six from partner, upside down count and attitude), and plays a club to you, as partner discards.   We can certainly set this hand if the diamonds are ready to run.  Can we set 2NT if declarer has a second diamond stopper?

Possibly.  We can’t give declarer a second diamond trick – two diamonds, two spades, and four clubs make 2NT.  But, we might be able to win a club, diamond, and four hearts.  Partner will need K10xx in hearts, which isn’t that unlikely.  South did turn down the invite, yet has already shown up with the diamond ace, and AKJ10x in clubs.  Maybe the full hand will look like this:

 

Which suit is more likely to run, diamonds or hearts?

Diamonds.  We can run our suit whenever partner has the nine, or any four card holding.  In contrast, to win four heart tricks, partner needs both the king and the ten, and four hearts. 

In any event, we shouldn’t have to guess here.  Partner has a chance to signal, and should help us out.  Hopefully, partner will discard a discouraging heart without the king.  At the table, East discarded the spade four – not extremely helpful, but South won the club king and continued the suit.  One more chance to signal!  This time, East discarded the heart eight, and it was clear to play diamonds. 

This is worth thinking about. 

    On defense, try to make your first discard as clear as possible.

Furthermore, declarer should have forced you to win the second club, limiting East to only one signal. 

Okay, you lay down the diamond queen, jack, three, eight.  Now what? 

The diamond four and nine are still out.  Partner may well have both of them, but partner might also have started with K93 alone.  Partner couldn’t afford to unblock with the nine, since, as here, you might not have the eight.  That’s okay.  Diamond to partner, heart through, and we set the hand two tricks.  The clearest way to signal for a heart is to play the diamond two now.  However, there is a very good reason to signal a bit less forcefully, with the diamond six.  Do you see why?

Here was the full hand:

 

  
Our West played the diamond six to partner’s nine.  East returned the four, and West underplayed this with the deuce, forcing East to win that trick.  Now a heart through would net +200.  Nice D!

Now I’ll turn to the first hand, looking first from the defender’s perspective:

 

Partner leads the club king, which declarer wins.  Next comes a diamond to the king, the spade ace (seven from declarer, six from partner), and a diamond, trumped by South with the three.  Declarer now trumps a club with dummy’s nine.  Plan the defense.

I’ll lead you in the right direction with a bunch of questions:

 

1.  How many clubs did South hold?  How strong are they?
2. Why did declarer cash the spade ace?
3. Who has the spade king?
4. Who has the spade two?
5. What is declarer’s hand?
6. What card do we hope partner holds?

For the club suit, partner overcalled two clubs, yet sold out to two hearts.  Partner certainly won’t hold seven or eight clubs, so South has at least five clubs!  Yet, South did not sit out two clubs doubled, so the clubs must be quite weak.  We’ve seen the nine in dummy, and partner has the king-queen, South the ace.  Of the remaining intermediate clubs, the jack, ten, and eight, partner will certainly hold most of them, and likely has all three. 

Cashing the spade ace seems like a very odd play.  It feels like declarer is hoping to cross-ruff, and, as is usual on such hands, cashing all the side-suit winners early.   I can’t imagine any hand where it was crucial to cash the spade so quickly, but that seems like declarer’s plan.  Since South cashed only one spade before this cross-ruff, partner has the spade king.  So partner started with K6 or K62 in spades. 

The spade six is consistent, playing upside-down count, with either holding, but it seems almost impossible to set two hearts if declarer is 1-6-1-5, so, let’s tentatively give South the spade two.  That leaves declarer with a hand like 72 AQJxx 2 A7xxx. 

South needs five trump tricks to make this contract, and will certainly get them if we play trumps.  Instead, we most over-ruff with the ten and try to promote a trump spot in partner’s hand.  The key card we want from partner – the trump eight. 

Here is my picture of the full hand:

 

   
We should ruff and play back the diamond queen.  What can South do?  Discard the spade?  Partner also throws the spade, and we continue with a high spade.  Trump with the jack?  Partner will likely throw a club.  If declarer tries to trump another club, we over-ruff, put partner in with the spade, and we’ll take two more clubs and a trump.  Notice, East can’t lose a tempo and play a spade here.  West will win, and play a high club, ruffed, and over-ruffed.  On a high card now, South trumps with the jack, and cashes the trump ace, to leave:

 

    
Exit a club and make poor partner lead into the trump queen-seven.  This is essentially what happened at the table. 

Here was the actual hand:

 

With South holding the club jack and the trump seven, West is in danger of getting endplayed in either trumps or clubs.  Here, the defense must be very careful.  After diamond queen, trumped with the jack, West must discard the spade king, or the hand can’t be set.  Not an easy defense.  Suppose West discards a club instead.  South can exit with the spade to partner (follow the play above to this point): 

If West exits a trump, South plays three rounds and scores a club trick eventually.  So West will likely lead a low club.  North discards, as you ruff with the four.  You force declarer again, who trumps with the queen:  What can West discard?  Another club?  Partner has to trump your winner and lead from the heart eight:

So, partner underruffs?  South plays heart ace, heart, to endplay partner.

This is a fascinating hand, but only after two poor decisions by South.  Cashing the spade ace was a blunder.  With the spade entry still in dummy, East can’t hurt South by leading a high diamond.  Then there is the bidding.   When the opponent’s have landed in my AJxxx suit, I defend.   Two clubs doubled rated to be much better for North-South than two hearts.  Here, two hearts was a real struggle, and barely came home.  Defending?  An easy +500.