Zhaozhou's Dog
狗子佛性 — How to Investigate "Nothing"
The Koan
僧问赵州："狗子还有佛性也无？"
州曰："无。"
僧曰："上至诸佛，下至蝼蚁，皆有佛性。狗子为什么却无？"
州曰："为伊有业识在。"
A monk asked Master Zhaozhou, "Does a dog have Buddha-nature?"
Zhaozhou said, "Wú" (无 — Nothing / No).
The monk said, "All beings, from the highest Buddha to the lowest insect, possess Buddha-nature. Why does the dog not have it?"
Zhaozhou said, "Because it has karmic consciousness."
Unpacking the Koan
This is the most practiced koan in the entire Chan tradition — the default hua tou (话头, "word head") given to beginners in the Linji school for over a thousand years.
The question seems theological: the monk is citing scripture (all beings have Buddha-nature) and asking why Zhaozhou contradicts it. But Zhaozhou isn't doing theology. He's not denying Buddha-nature as a doctrine.
Wú (无) is not "no" as a factual answer. It's a hua tou — a word that cuts through the thinking mind. It's the sound a sword makes when it severs the chain of conceptual thought. Before you can think about what it means, it's already done its work.
The monk's follow-up question ("why not?") shows he's still thinking. Zhaozhou's second answer ("karmic consciousness") points to the obstacle: the very mind that asks, reasons, and wants an answer.
Why It Matters
The genius of this koan is that it gives you nothing to think about. There is no clever interpretation. There is no "correct answer." Wú is not a concept — it's a practice.
In hua tou practice, you sit with this word — "Does a dog have Buddha-nature? Wú." — and let it burn through every layer of understanding. When you've exhausted all your ideas about what Wú means, something else opens up. That "something else" is what Chan points to.
As Master Sheng Yen said: "Wú is not nothing. Wú is everything before it becomes something."
Practice Pointer
Sit quietly. Ask yourself: "Does a dog have Buddha-nature?" Then answer: "Wú." Don't think about what it means. Just hold the sound, the question, the doubt. When thoughts arise, return to "Wú." Let it be the only thing in the universe.