He later lost a trick to the club king for down one.
South took the club king and tried for the only real chance.
When he played low, East won with the 10 and shifted to the club king for want of anything better.
West's lead of the club king was normal, though not best.
She won with the queen and led the club king.
East therefore allowed the club king to hold, but it did him no good.
He made the right first move by leading the club king.
East was forced to take the club king and could do nothing effective.
West must have held up his club king until the third round, and would do best to lead a low heart.
And then he would have known that it was West who held the club king.