I don't remember if East overcalled on not on this deal but whatever happens I'm going to bid 4♠ at my earliest opportunity.  South's hand is weak, but distributional with excellent trump support.  You have 7 losers and probably only one chance to bid so make the most of it.  Declarer should only lose two hearts and a club but the opposition will play a forcing game.  You must plan the play early before playing a card.  The ♣K is an attacking lead good when the opo bounce the bidding showing distributional strength rather than high card points.
North wins the first trick with the CA and draws trumps in two rounds, ending in dummy.  A small ♦ towards the A-J, (I hope all the Wests automatically went up with the K or Q!) and a ♦ ruff exposing the bad break.

I don't agree with partners Spade opening but it worked on this occasion.

This hand came up last week.  With 20 HCPs South has a problem, the void makes it unwise to open 2NTs and the suits are too short to be worth a two opener.  1♥ is the answer.

West and North don't have much problem finding the Pass cards in their BB and the heat is on East.  You might choose just to bid your clubs at the 2 or better 3-level but there is one gadget most of us play which fits the bill here - the Unusual 2NTs.  This shows the 2 lowest unbid suits, in this case the minors.

Back to South.  It’s usually a good idea to raise the anti when the opposition are asking each other to bid plus this is such a strong hand it deserves one more try.  3♠ fits the bill.  When South bids, East is no longer forced to bid and can choose to pass.   In fact a new suit at the 3-level is unconditionally forcing and North actively prefers spades, you have now found that elusive 4-4 fit so really should bid 4♠.  Its one of those dilemmas that one meets at the table from time to time.

Against sleepy defence you might slip 10 tricks through but 9 should be just there.

An interesting slam needing one finesse to make.  And when the finesse is in the trump suit there is no escaping it.

This is the shape hand which should make West tingle and start sniffing around for a possible slam.  East has must recognise his duty on this hand to show his 3-card diamond suit.  When West finds out about the double suit fit he can afford to ask partner for aces as he can always stop in 5♦, admittedly he will have gone past the optimum contract and score which would be 4♠ if the other pairs are not bidding the slam, but it’s worth it. 

Nothing venture - nothing gain.

South is on lead against 6♠ and selects an unbid suit. NS have a lot of information about the EW hands.  West is marked with 5 or probably 6 diamonds and 4 spades so is short in the unbid suits.  As South holds 8 HCPs and partner possibly has an ace because they have stopped in six, shape must be making up for the lack of points.   In this situation I would usually choose an attacking lead like the ♣K, giving up the chance of two tricks in the suit but hopefully promoting one quick trick.  A passive lead is a heart which works well on this hand as it happens because the losing heart will disappear on the long diamonds after trumps have been drawn.   Of course the spades have to be tackled the correct way.  The correct way to play the suit is small towards the AQ.  If declarer makes the mistake of leading the ♠J, South must punish him and cover with the King which is trapped anyway. 

Why is the J the wrong card?  Because it does not have the 10 behind it.