A monk once asked Joshu, "Please instruct me."
Joshu asked "Have you eaten your meal?"
The monk replied "Yes."
Joshu then told him "Then go wash your bowls."
Background on this Koan:
We meet Joshu again in this koan. As I understand it, I thought I read somewhere the monk asking for instruction was either a senior monk or someone new to the monastery. Either way, he was seeking further instruction from Joshu.
What some people think:
The book Gateless Gate provides several answers and is a good way to outline what some people think about this koan. Most koans are nearly always talking about the dharma and/or essential nature. In one form or another. In this case you might say "Have you tasted enlightenment?" "Yes". This is more of that Mark Twain style double speak. Except these fellows are from a much older time and an older culture.
1. Essential view. The Gateless Gate says in regards to essential view. I believe the book is trying to remove dualistic concepts and indicate that all is one.
2. Kensho Sickness. The Gateless Gate also indicates "Kensho Sickness". It doesn't call it that, but I've heard that term before possibly from "The Three Pillars". In a way, they are saying "Wash away the delusion." The first monk had his meal, he tasted Kensho. It's natural to feel proud about it and shout it out and boast it. These are what I've heard called Kensho Sickness. It causes one to lose focus and eventually could possibly lose any benefit of that understanding. Then it's gone and one must reacquire it.
Other interpretations I heard include honoring the other monks in the monastery. When you perform the simple act of washing your bowls, you are honoring the next monks who will benefit from these clean bowls. Washing the dishes can be a form of moving meditation as well. When meditating we mimic the Buddha and in self power / other power we join in a communal effort of total understanding.
My thoughts on this koan:
My thoughts are similar to that "Kensho Sickness" version. One should accept the small measure of understanding and then continue to practice. As I understand it, there are deeper and deeper understandings. It has been said that first taste of understanding is like someone recovering from eye surgery. You can see things but they are not in focus. Then with a little more understanding, they come into focus but now you can see blurry things farther away.
"Have you tasted enlightenment?" "Yes" "Then continue practicing." I think its that simple.