Vulnerable, None; South dealer
Contract: 6
by South
Lead: 
10
One of the standard book plays is what might well be described as the submarine, trump play.
This play consists of leading a low trump from both hands so as to continue to hold full control. This hand from «Test Your Bridge» is a simple illustration of this play.
South is faced with a sure loser in trumps at his six-heart contract. He can’t afford to lose another trick so he must ruff the spade lead. If he proceeds to cash the ace and king of trumps, he will have to lose a spade later on, unless something especially good happens in the minor suits.
There are two other ways to play the hand and both work. One is to lead a diamond to the ace, ruff a spade, diamond to the king, ruff the last spade, club to the ace and then lead trumps.
The simpler play is to submarine a trump immediately. Then draw trumps and discard the last two spades on dummy’s clubs.