finesses in bridge. basic idea of how to play them
Playing a finesse in bridge gives you at least a fifty per cent chance of making a trick and sometimes more.
Let's imagine we want to take a trick with the king of spades in the north hand and we are declarer with the south hand.
It's quite obvious that, if we play the king from north, east will play low and we will play low from the south hand but west would win the trick with the ace of spades.
Instead we play a low spade from our own, (south), hand towards west and wait to see what s/he does. If west plays the ace our king becomes master but if west plays low we play the king and it takes the trick.
There is a generally accepted maxim in bridge that "second hand plays low" although there are exceptions but either way our king of spades has a fifty per cent chance of making depending upon who has the ace. It's fairly obvious that if east holds the ace we will never make our king but a finesse gives us half a chance.
As mentioned above the chances could be even higher. Suppose, during the bidding, that west had actually bid spades. The odds of him or her having the ace would be much greater. This type of finesse is called a marked finesse for obvious reasons.
There are other types of finesse in bridge such as a trump finesse. This is where you lead a high card from dummy when you have none of that suit in your hand. If the player to your right covers it with a higher card you trump it but if they play low you let it run. Please note I've only covered the basic finesse here as this is a good starting point for a learner.