Wikipedia lists this as a possibility, that “mu” in archaic Japenese was “wu” the sound that a dog makes. While this also makes the koan a pun, I think it now works even better as a koan:
Q: Does a dog have a Buddha-nature?
A: Woof!
Does ‘Woof!’ mean ‘yes’? Does it mean ‘no’? It’s still just ‘mu’, but better. (For one thing, we’d expect an English-speaking dog to respond to the question.)
Wikipedia lists this as a possibility, that “mu” in archaic Japenese was “wu” the sound that a dog makes. While this also makes the koan a pun, I think it now works even better as a koan:
Q: Does a dog have a Buddha-nature? A: Woof!
Does ‘Woof!’ mean ‘yes’? Does it mean ‘no’? It’s still just ‘mu’, but better. (For one thing, we’d expect an English-speaking dog to respond to the question.)