"Tokusan once called on Ryutan to ask for instruction and stayed until night fell. Ryutan said, 'It is getting late; you had better leave.' At last Tokusan said good-bye, lifted up the door curtain, and went out. Noticing that it was dark, he turned back and said, 'It is dark outside.' Ryutan thereupon lit a candle and handed it to him. Tokusan was about to take it when Ryutan blew it out. At this Tokusan was all of a sudden enlightened. He made a bow. Ryutan asked, 'What realization do you have?' Tokusan replied, 'From now on I will not doubt the sayings of any of the great Zen Masters in the world.'
The next day Ryutan mounted the rostrum and declared, 'Among the monks here there is a fellow whose fangs are like swords, and whose mouth is like a bowl of blood. You may strike him with a stick but he will not turn his head. Some day in the future, he will establish his way on a steep and lofty peak.'
Tokusan then took out his notes and commentaries on the Diamond Sutra and in front of the monastery hall he held up a burning torch and said, 'Even though one masters various profound philosophies, it is like placing a single strand of hair in the great sky; even if one gains all the essential knowledge in the world, it is like throwing a drop of water into a deep ravine.' Taking up his notes and commentaries, he burned them all. Then he left with gratitude."
- Zen Koan (Gateless Barrier, #28/page 201)