One old story talks about a famous Zen priest in ancient times in Japan. Though he was highly celebrated as a great lecturer he was as well very full of himself. Dissolving of the Ego and accumulation of the knowledge don’t always go hand in hand in which case great, inflated ego came along with great reputation.
One day during his lecture tour, zen priest visited an abbot. It was raining very hard that day. Upon arriving at the temple, he left his shoes and his umbrella inside the door. Entering the master’s quarters, he bowed and was offered tea.
The old abbot looked at him and said:
"Really bad weather out today. I assume you brought your umbrella."
"Oh, yes, of course."
"By the way, on which side of your shoes did you leave your umbrella?"
The great lecturer was astounded. He didn't know what to say. His mind was so full of himself that he didn't even know where he left his shoes or where he left his umbrella.
For most people this seams as nit-picking. But it is not! Zen training is not only about zazen, kinhin or samue. It is extended to each moment, to each action and non action. Only so we stay in a present moment, with full mindfulness, dissolving the ego on the go.
This is true Zen training.