This is aHand:

This set of deals (and another series of six deals elsewhere in this edition of VBlue) is all about defense against 3NT contracts.

The principles involved form the bedrock of defensive play. Let's list some of these ideas, which we hope to crystallize with these deals.

Leading from long suits (top of sequences – if you are lucky enough to own one; fourth-highest from broken suits);

Third hand playing high to help establish partner's suit;

Returning your partner's suit.

On these six deals you will be sitting as the third player, working out what to do when partner leads against West's 3NT. In the second series of six deals you will be switched to being the opening leader.

Bidding.

West opens 1NT in fourth seat (16 points and a 4∙3∙3∙3 pattern). East, holding 10 points and a decent suit, raises that to 3NT without stopping to admire the view.

Play.

Our partner leads a low Heart against 3NT, which we must assume to be from his longest suit. Holding a broken suit he leads the fourth-highest card; had he held a sequence (such as ♥J 10 9 and others) he would have led the top card.

Declarer calls for dummy’s ♥4 and we must not forget to play the ♥K. If we were too mean to play our highest card (by playing the ♥10 instead, say) West would have an easy ride as he'd win a cheap trick with the ♥J and then would have tricks to burn (a Heart, two Spades, five Diamonds and two Clubs on top).

The usual rule to guide us here is:

Third hand high

meaning that we should respond to the opening lead by playing our highest card to help develop partner's suit. (We will expand on this important theme as we proceed).

After correctly playing our ♥K (which wins the trick) we must lose no time in playing back another Heart (return your partner’s suit).

The correct card to lead back is the ♥10. When we hold two cards remaining we should always lead the higher, although on this layout of the cards, on this deal, it doesn't actually matter.

North has to keep track of all the Hearts (by counting them). As he does so he realizes that all of them are winners (yes, even the lowly ♥2) and the defense have the first five tricks before a bemused declarer gets a look in.

One down in 3NT. If we were that way inclined we could always sympathize with West. "Tough luck, pal"