When Hyakujõ Oshõ delivered a certain series of sermons, an old man always followed the monks to the main hall and listened to him. When the monks left the hall, the old man would also leave. One day, however, he remained behind, and Hyakujõ asked him, "Who are you, standing here before me?"
The old man replied. "I am not a human being. In the old days of Kashyapa Buddha, I was a head monk, living here on this mountain. One day a student asked me, 'Does a man of enlightenment fall under the yoke of causation or not?' I answered, 'No, he does not.' Since then I have been doomed to undergo five hundred rebirths as a fox. I beg you now to give the turning word to release me from my life as a fox. Tell me, does a man of enlightenment fall under the yoke of causation or not?"
Hyakujõ answered, "He does not ignore causation."
No sooner had the old man heard these words than he was enlightened. Making his bows, he said, "I am emancipated from my life as a fox. I shall remain on this mountain. I have a favor to ask of you: would you please bury my body as that of a dead monk."
Hyakujõ had the director of the monks strike with the gavel and inform everyone that after the midday meal there would be a funeral service for a dead monk. The monks wondered at this, saying, "Everyone is in good health; nobody is in the sick ward. What does this mean?" After the meal Hyakujõ led the monks to the foot of a rock on the far side of the mountain and with his staff poked out the dead body of a fox and performed the ceremony of cremation.
That evening he ascended the rostrum and told the monks the whole story. Õbaku thereupon asked him, "The old man gave the wrong answer and was doomed to be a fox for five hundred rebirths. Now, suppose he had given the right answer, what would have happened then?"
Hyakujõ said, "You come here to me, and I will tell you."
Õbaku went up to Hyakujõ and boxed his ears. Hyakujõ clapped his hands with a laugh and exclaimed, "I was thinking that the barbarian had a red beard, but now I see before me the red-bearded barbarian himself."
Not falling under causation: how could this make the monk a fox? Not ignoring causation: how could this make the old man emancipated? If you come to understand this, you will realize how old Hyakujõ would have enjoyed five hundred rebirths as a fox.
Not falling, not ignoring:
Two faces of one die.
Not ignoring, not falling:
A thousand errors, a million mistakes.
At first glance this comes across as a very simple parable about a monk who gives an incorrect answer. The monk was asked whether an enlightened man is subject to the law of cause and effect. When he answered "no," he was punished with five hundred lifetimes as a fox. He asks Hyakujo to give the answer that will free him from this punishment. Hyakujo delivers the answer, and the old monk is freed. How simple and charming right? But notice Mumon dismisses both answers. "Not ignoring, not falling: A thousand errors, a million mistakes." So what is up?
It's worth keeping in mind that many Buddhists believe that the law of cause and effect (karma) is something that one can eventually free themselves from. This seems to be presented here in the monk's statement, that the enlightened man does not fall into the law of cause and effect. How wrong he appears to be; his incorrect answer causes his "punishment." He is shown to be both cause and effect of his own circumstances. Hyakujo's statement, that the enlightened man does not ignore cause and effect, seems to contradict the old man's, and is the impetus that triggers his freedom from the life as a fox. Hyakujo's answer, not to ignore it, does not acknowledge being subject to cause-and-effect, but it does not imply any freedom from it either.
Understand that freeing oneself from cause and effect is a delusion born from the mistaken belief that cause and effect is something that happens to you, and that there is a you for it to happen to. We tend to view it as the circumstances that surround us, and which we bump into. The old monk sees his circumstance of being reborn as a fox as something that was done to him. He does not see that he himself is both cause and effect. He doesn't see that he is an element of cause and effect, not a subject of it. He views himself as tangled in the cloth of cause and effect, and fails to see that he's just one more thread in the tapestry. The enlightened man is free, so when presented with the question, he answers with what seems as though it must be the truth: that the enlightened man does not fall into cause and effect.
His answer is correct, but it is born of wrong-mindedness. He buys into the either-or nature of the question. He buys into the self-oriented view of the universe. The enlightened man doesn't "fall into" cause and effect any more than you "fall into" growth. You are born growing, and you grow throughout your life. You do not "fall into" cause and effect, you are not affected by it, you are a part of it. Hyakujo's answer is also correct: the Enlightened man does not ignore cause and effect. He couldn't even if he wanted to; it is a fundamental part of his entire existence.
Does the enlightened man fall into cause and effect? If you answer yes or no, you've already made "a thousand errors, a million mistakes" just in accepting the question. Just by considering the question, you've already taken on the view that the self is something other than cause and effect. So what of the belief that you can free yourself from cause and effect (karma)? In the sense that the ordinary person views it, it is nonsense. Consider yourself as you are now. You are very much entirely within the fabric of cause and effect. Most likely, even if you have an intellectual understanding that you are a part of it, your immediate feeling is that it's something that happens to and around you. If you are subject to cause and effect now, how can it ever not be the case? If you work through your life to overcome it, or through multiple lifetimes as some believe, then you are working as a being of cause-and-effect to become a being that isn't. In other words, you're trying to cause yourself to overcome it. How can you cause yourself to no longer be affected by karma, when your efforts are the cause, and your supposed freedom from cause and effect is the effect?
You cannot free yourself from something that doesn't bind you; you can only free yourself from the delusion that it binds you. Mumon says that Hyakujo would have enjoyed his five hundred lives as a fox. Of course he would; he views himself as part of the tapestry that is cause-and-effect, not as a subject to it. Whatever currents of change he is part of, he is free from the delusion that it happens to him, and is therefore free to enjoy his existence no matter what circumstances he finds himself in.
The final segment of the koan features a student who sees the truth, and asks the question that penetrates right to the heart of the matter. "If he had given the correct answer, what then?" He is testing his teacher. He understands that the question is a trap, and that that choosing "correct" or "incorrect" is stepping firmly into that trap. He is asking his teacher a question, but the details of the question don't matter. The real challenge is: "if you answer this question, you're agreeing to the terms of 'correct' and 'incorrect,' and thus have stepped into the same trap as the old monk." This is presented as a challenge to Hyakujo, but in reality it is a challenge to you, the reader. This is a piece of the koan to push you to question the simplicity of the story that has come before it.
Hyakujo invited Obaku up to the stand, so he might "tell him the answer." Hyakujo was going to hit him for asking a misguided question. By coming forward and hitting Hyakujo first, Obaku shows that he knows his question was nonsense. He is saying: "I know you are going to hit me, and I know why." By beating Hyakujo to the literal punch, he displays his own understanding to his teacher.