East put up the king and played a second trump.

West goes in with his king and plays a second trump.

The winning line, seeing all four hands, was to play a low trump to the ten.

He led to the heart ace and played a trump.

Next he played a trump to the jack, king and ace.

Sometimes, it will be necessary to cross check whether somebody played a trump or not.

A player who cannot follow suit must play a trump if possible.

A player with no card of the led suit may play a trump.

Any player who has no card of the suit led must play a trump if they can.

No doubt East thought that he could leave it to his partner to play a trump.