A monthly magazine Shuzen (Zen Practice) consisting of sermons by Oka Kyugaku came out for seven years until his death in 1953. They were delivered by this famous Zen master in his retirement at Shuzenji Temple in Izu Peninsula, Japan. The Key to the Treasury is one such sermon.
The Giving of the Precepts is a very solemn matter. Originally, these are rules for worldly conduct which are in fact from the beginning natural to man, but it is only when they have been heard from a senior monk and deeply assented to in the self, that they can really become one’s own. This is brought about for the first time at the ordination ceremony. The word ‘senior’ means the Buddhas of the three worlds and the patriarchs of history; and the Conferring means that they transmit what they practise themselves; Receiving means that what has been transmitted by the seniors is the right way to act. The heart of the occasion can be put like this: What is received is the tradition; the tradition is enlightenment; so taking the precepts is enlightenment of the Buddha-heart. So it is explained, and so it is. Thus on the occasion, the Buddha-heart is manifested, in its beauty and radiance in himself. So it is said that the ceremony is the self-opening of the treasury of one’s own self, and again that it is the Buddha-treasure in all beings.”