It would be easy to look at this koan superficially and come away thinking, “Oh, the bird’s chirping, that’s the truth of the universe.” That is not what this koan is about. If you are going to see into a koan, you first have to understand what the questions are.

Beginning with the main case, “Xuansha was informally addressing his monastics….” The footnote to that says, “It is within the mundane that the pure light is at its brightest.” This is referring to the teacher informally addressing his students. There are five ways that teachers and students interact. Dokusan is a very formal face-to-face encounter or direct pointing. Discourse, also formal, is a public address that points to what is dark to the mind but radiant to the heart, so a very different way of listening is required. It’s not intellectual or rational, not linear or sequential. Then there’s dharma combat, which is a face-to-face public encounter and dialogue, very much like dokusan except that it is public. There’s mondo, question and answer sessions on some point of the dharma. Finally, we have the informal or casual encounters that take place in our everyday lives. And it’s these casual encounters that can be the most powerful because students tend to not be on their guard. They are open and receptive, unlike the way they come into dokusan. It takes years before students stop rehearsing their answers and begin to trust the unknown.

Xuansha was informally addressing his students when he heard a swallow sing. The footnote to that says, “Song of the mystical subtlety.” The word mysticism comes from the Greek mystos which means seeing with the eyes closed. It means achieving communion or identity with or conscious awareness of ultimate reality, of spiritual truth. It’s a direct intuitive experience or insight.

Xuansha said to the assembly, “This is the profound dharma of real form.” The footnote to that says, “Pervading the universe, vast and without edges.” In this same fascicle there is a quote from the Lotus Sutra in which Buddha says:

Just Buddha with Buddha are able to exhaustively investigate the real form of all phenomena. What is called all phenomena or all dharmas are the form of suchness. The nature of suchness, the body of suchness, the power of suchness, the making of suchness, the cause of suchness, the condition of suchness, the result of suchness, the karma of suchness, the equality of the very beginning and the ultimate of suchness.

Dogen, commenting on this passage, said, “The Buddha’s words ‘equality of the very beginning and the ultimate of suchness’ are a free expression of the real form of all phenomena.” He is telling us what the real form of all phenomena is about.

Xuansha continues, “It skillfully conveys the essence (or principle) of the true teaching.” The footnote to that says, “When has the buddha principle ever been a principle?” We should ask the question: what is a principle? A principle is an underlying law, an assumption that is required in a particular system of thought. It’s a standard of moral and ethical decision making. It’s a basic way in which something functions. It’s a primary source.