Matajuro Yogyu was a son of a famous swordsman. But his father disowned him because he failed to learn.
So Matajuro went to Mount Futata where he found the famous swordsman Banzo.
So the Master said to him, “So you wish to learn swordsmanship under my guidance. But you cannot fulfill the requirements.”
“But if I work hard, How many years will it take me to become a Master?” the youth persisted.
“The rest of your life,” relied Banzo.
“I cannot wait that long,” argued Matajuro, “I am willing to undergo any hardship if only you will teach me. If I became your servant, how long might it be.”
“Oh, maybe, ten years,” Banzo relented.
“ If I work far more intensively, How long would it take?”
“Oh, maybe thirty years.” Said Banzo.
“Why is that?” asked Manatjuro. “First you said ten years, they you say thirty years. I will under go anything to master this art in the shortest time!”
“Well,” said Banzo, “In that case you will have to stay with me at least seventy years.”
“Very well,” declared the youth, understanding at last that he was being rebuked for impatience, “I agree.”
Matajuro was told never to speak of fencing and never to touch a sword. He cooked for his master, washed the dishes, made his bed, cleaned the yard, cared for the garden, all without a word of swordsmanship.
Three years passed. Still Matajuro labored on. Thinking of his future, he was sad. He had not even begun to learn the art to which he had devoted his life. But one day Banzo crept up behind him and gave him a terrific blow with a wooden sword.
The following day, when Matajuro was cooking rice, Banzo again sprang upon him unexpectedly. After that, day and night, Matajuro had to defend himself from unexpected thrusts. Not a moment passed in any day that he did not have to think of the taste of Banzo’s sword.
He learned so rapidly he brought smiles to the face of his master.
Matajuro became the greatest swordsman in the land.
From Zen Koans. 1973 page 80