first things a new bridge player has to learn is that is that it is unwise to lead out unsupported honour cards. Holding K975, the lead of the king will usually achieve little more than a premature death of the king. It’s better if your partner leads the suit, allowing you to play after the opponent on your right. This way your king will win a trick when RHO has the ace. And it is even better still if the opponent on your left leads the suit. This way you are last to play to the trick, making it certain that the king will win a trick.
The same idea applies when you have a combination of honours, for example, J65 in your hand and Q82 in dummy. If you tackle the suit you will usually end up with nothing. But if an opponent leads the suit, you are sure to take a trick. Many techniques in card play are doing nothing more than forcing the opponents to lead suits like this. Consider this deal.
West leads the queen of hearts against your four spades. Since you have a heart loser, your contract depends on not losing three diamond tricks. Left to your own devices this is not possible. You might lead a low one towards the jack but East will win with the ace and when you lead a low one towards the queen, West will take the king, removing all hope. So you need to force the opponents to lead the suit.
Like this. Win the heart lead and draw trumps in two rounds. Next remove the opponents’ club exit; play the ace and king of clubs and trump dummy’s remaining club. Now you can take your other heart winner and exit with a heart. This leaves the opponents stymied. If they lead a diamond, you are sure to make a diamond trick, and if they lead a club you can trump in dummy and throw a losing diamond from hand. Either way your contract is guaranteed. Similar here.
West leads a low club against four hearts. How would you play?
If you try your luck in spades, you will find that today is not your lucky day. A spade to the king loses to the ace and a spade to the jack loses to the queen for one down. Yet all the while your contract is certain. Play out the ace and king of hearts, leaving one trump outstanding, take the other winning club and run all the diamonds. If no one has trumped in, exit with a trump. Whoever wins must now open the spade suit for you, guaranteeing you of a trick in spades, or lead a club, allowing you to trump in one hand and discard a losing spade in the other. Either way you have 10 tricks.