A True Dragon Appears In The Dark

One evening, Tokusan sat silently outside the teacher's room.  The teacher, Ryutan, asked, "Why don't you go back to your room?"  Tokusan replied, "It's dark."  Ryutan lit a paper lantern and gave it to Tokusan. 

But as Tokusan grasped the lantern, Ryutan immediately blew it out.  Tokusan was greatly enlightened and made prostrations.  Ryutan asked, "What have you seen?"  

Tokusan said, "From now on and henceforth, I will never under the heavens doubt the tongue of my old master."  

Although your efforts to engage the way should be put to rest,
With a grandmotherly mind, Ryutan spoke on and on for you.
Loving the true dragon, the true dragon appeared
In a single scene of blowing out a lantern.  

- Volume 9, Case 24 from the Eihei Koroku (Dogen's Extensive Record)