This is a tame auction for a wild hand. Most inexperienced partnerships have not discussed the meaning of a cue bid overcall of a preempt.  So E settles for 3♦ . W has a difficult decision over 4♠ , but chooses to pass at this vulnerability. At equal vulnerability the odds don’t favor competing to the 5 level. 4♠ makes, but 5♥ or 5♦ does as well from the EW side. (The law of total tricks in action)

Experienced pairs have faced this dilemma before and agreed that 3♠ cue bid shows a strong Michael’s hand ♥ and minor; or use a convention called “leaping Michael’s “.  E would jump to 4♦ which by agreement shows a strong hand with ♥ and ♦ .  That would inspire west to bid ♥ at the five level.

This is an unfortunate hand for NS in a couple of ways. East has an obvious lead, with partner playing high-low to show a doubleton.  On the third diamond declarer has no winning option. The defense will collect two ♦ tricks And two ♥ tricks for -1.

Those pairs that do not use transfers may get lucky as West may not find a ♦ lead at trick 1

Bridge bidding is a lot like chess, in the each bid has an offensive and a defensive component. Opening 2NT is intended as purely offensive, but it also deters the opponents from intervening because of the level and strength of the bid. 3♦ on the other hand is primarily defensive, anticipating the opponents have values, and interfering in their expected auction; often forcing the opponents to guess. but you are guessing as well.

Here W can bid 1♠ (wait and see), 3♠ (make em guess), 4♠ (I’m guessing they have game). 
The reasons to bid 

The west hand is strong enough to open 2♣ , but W chooses 1♦ , providing room to show all three suits if necessary.  The danger in not opening 2♣  is that the hand gets passed out after. E has plenty and guides the  pair  to 3NT.  After N 1♥ bid, some E will pass (this is called a trap pass), hoping partner will “double”, any they can then pass and get a top score.  
As bad as it looks for NS, it will be very difficult for EW to take 9 tricks on defense, against 1♥ doubled.  That’s what it would take to get a better score than making 3NT.

There are some hands where both sides have offensive powerhouses, and points don’t matter as much as trick taking potential, and listening to the bidding. N has no problem jumping to 4♠  over 3♥ , but then E competes to 5♥ vulnerable (lots of ♥ and not many spades) and expecting to make or go down no more than 1. Turns out E bids 5♥ because she knows partner has no more than 1 spade and can visualize losing no more than 3 tricks.

N now has to choose between bidding 5♠ And doubling 5♥ . When an opponent is confident enough to compete to the 5 level VUL, I take note. I expect to set 5♥ taking 2 aces and partner winning a club.  But if so, I’m likely to make 5♠ ….so there!
Plan the play after E leads A♥ .

With a weak hand a 5 card support it is usually best to jump to game. Frankly you don’t know if your bid is ‘to make’ or preemptive…but it doesn’t matter.  Call it bridge dynamics or “the law of total tricks”. When Our side has a 10 card fit , the other side is likely to have one as well . That’s 20 total tricks, or if our side can take 10 tricks so can the other side. If our side can only take 9 tricks(go down 1) the other side can take 11(make 5). By jumping to 4 we score our game when we can take 10 tricks, and make it difficult for the opponents to find their game fit when we can’t make game.

Let’s see how “the law “works on this hand. EW has a 10 card fit in spades. NS has an 8 card fit in either minor . That’s 18 total tricks. EW makes 4♠ losing 2♥ and 1♠ .  NS can make 2♦ (8 tricks), losing 2♣ , club ruff, 1♦ ,1♠ . 

I like to upgrade with 17 and a 5 card suit. Is N going to respond to 1NT? The 5 card ♦ Suit would inspire me. At any rate, in 3NT after a spade lead, count your tricks and decide where your extra tricks are likely to come from.

Examine this hand very carefully! The auction as described is sensible. West either bids 3♦ naturally or has a convention that ends in 3♦ .Making 3 or 4. But what if E opens the 11 point hand 1♥ …2♣ by S….3♣ limit+ or 4♣ splinter by W ( or 4♥ Directly, having full game values with singleton club). 4♥ is making at most tables.

There is a good argument to be made for opening 11 point hands with a 5 card major.  Another way of looking at it is it’s less risky to open this had than to overcall with it at the 2 level.

E hand is close to a 1♥ opener had the k♣ been the K♠ . And W with 4 tricks and 3 hearts has an easy raise to game. Take a minute and figure out a line of play to make 6♥ on a ♠ lead. Trump are 2-2.

I usually get these hands wrong at the table as NS . My inclination, supported by evidence, is to get in the auction as N, even as a passed hand, with 44 in unbid suits.  It accomplishes the goal of moving the opponents from a NT contract to a “poorer scoring” minor suit contract. On this hand however, the combination of no diamond stopper and most things working in the other suits, clubs scores better.

If N passes rather than double E 1NT will likely end the auction.

The 3♥ bid by east is a cue bid with a specific meaning “Bid 3NT if you have a ♥ stopper”. East can picture 8 tricks and clearly count on West for a ninth after the double. But a ♥ stopper is necessary.  
note that it is reasonable for North to interject a preemptive 3♥ at this vulnerability, and that gums up the works for EW. E might choose to bid 5♦ after that.

Pass or bid? What?

South with game forcing values, a 4 card major and longer minor, bids the minor first (2♣ ) planning to show ♥  later.  West jumps to 4♠.  N has described her hand, and passes.  S, the decision maker in this auction doubles with no clear offensive option and doing her best to protect the known  game values.  This works out great for NS as 4♠ * goes down 3 tricks, as E has no help for declarer.  

Note that EW get their best result  by staying completely out of the auction, allowing NS to bid to an unmakeable game. It is a frustrating game!