Buddhadharma

Shitou Xiquian was asked by one of his disciples, "What is the essential meaning of buddhadharma?"

Shitou replied, "No gaining, no knowing."

Daowu asked again, "Can you say anything further?"

Shitou answered, "The expansive sky does not obstruct the floating white clouds." 

The wide expanse of the sky does not obstruct the passing clouds. It lets them float freely. I think these words from the koan fully express the meaning of buddhadharma.

In other words, it means to be free from the ideas we make up in our head. I call this opening the hand of thought. When we think of something, we grasp it with our minds. If we open the hand of thought, it drops away.

The koan describes what zazen is quite well. What on earth is Buddhadharma,? Fundamentally, it is just opening the hand of thought. And to practice opening the hand of thought concretely with the body and mind is zazen. So buddhadharma means "what awareness is," are perhaps "way of awareness."

When we let go of our thoughts and become vividly aware, all the illusions that create desire, anger, and group stupidity vanish immediately.

Chapter 8 - The Wayseeker: Section - Seven Points of Practice, page 140-143, Opening the Hand of Thought by Zosho Uchiyama.