West played low, which would perhaps have been right if East had held the king.
When West played low there was something to think about.
West played low, usually the right move in this situation.
West played the king, and South allowed this to win, a key move.
South then led the club three, and West played the five!
He led that suit and when West played low put up the king.
When West played low, there was a long break in the action.
West played his last heart and South was in control.
Next he led a club and won with the jack when West played the nine.
West should have played the 10, leaving South less confident.