Cue Bid 

South opens a weak NT. North forces to game (with some slam interest) with 3S and South (with good cards for a slam in Aces and a King) cue bids 4 Diamonds. North rebids 4 S (denying the Ace of Hearts) which becomes the final contract. 

Want a good reason not to lead a singleton trump? Look no further than here. On a passive diamond (or even club) lead, NS have to guess the spades AND the hearts to make 12 tricks. 

Rule of 14

West opens 1S and East would like to bid 2H but using the Rule of 14 the hand is not strong enough. A ‘dustbin’ 1NT keeps the bidding open to hear the rebid.  If West rebids 2C then East can rebid 2H.  As West is balanced with 15 pts it’s a pass.

Defence

Assuming Diamonds are led, (4^thhighest from longest suit) which cards should East discard?  Discard 2 Clubs.  It is hoped that South will lead a Club which will set up E/W 7^thtrick and the 1NT contract will make.  If South switches to a Spade it sets N/S 7^thTrick and the contract is defeated.