Zen Master Man Gong built a small temple, Jung Hae Sa, on the mountain above Su Dok Sa, specifically for long retreats. Because the monks at the temple practiced most of the time, there was little money and the monks periodically had to go out to the surrounding villages and ask for food.
But when Ko Bong Sunim went out to get rice, he would then sell it and go out drinking. After he was totally hammered, he would return to the temple and complain, "This temple is no good! Man Gong doesn't understand anything! He's low-class!"
One time Zen Master Man Gong showed up during one of Ko Bong's tirades and screamed at him, "What do you understand?" Ko Bong Sunim was silent.
Man Gong Sunim shouted, "KO BONG!"
"Why are you always insulting me behind my back?"
Ko Bong looked completely surprised and offended. "Zen Master! I never said anything about you! I was talking about this good-for-nothing Man Gong!"
"Man Gong? What do you mean, Man Gong? I'M Man Gong! What's the difference between Man Gong and me?"
"KAAAATZ!" Ko Bong yelled, loud enough to split everyone's eardrums. That ended it.
"Go sleep it off," Man Gong Sunim said, and he left the room.
Zen Master Seung Sahn commented on this story:
My teacher was always drunk, used abusive speech, and showed disrespectful behavior. But he always kept a clear mind. “Man Gong? What’s the difference between Man Gong and me?” “KAAAATZ!” That katz is very important — better than money or bags of rice. Ko Bong completely believed in himself.