Mokurai, the master at Kennin temple had a young protégé named Toyo. Every morning and evening, Toyo observed the older disciples visit the master’s room to receive instruction in sanzen and to be given koans to prevent their minds from wandering.
Toyo wished to do sanzen as well, and Mokurai told him, “Wait a while. You are too young,” but the 12 year-old child insisted until the teacher finally consented.
In the evening little Toyo went at the proper time to Mokurai’s sanzen room. He struck the gong to announce his presence, bowed three times outside the door and went to sit before the master in respectful silence.
“You can hear the sound of two hands when they clap together,” said Mokurai. “Now show me the sound of one hand.”
Toyo bowed and went to his room to consider this problem. From his window he could hear the music of the geishas. “Ah, I have it!” he proclaimed.
The next evening, when his teacher asked him to illustrate the sound of one hand, Toyo began to play the music of the geishas. “No, no,” said Mokurai. “That will never do. That is not the sound of one hand.”
Thinking that the music coming from his window might distract him, Toyo moved to a quiet place. What can the sound of one hand be? He happened to hear some water dripping. “I have it,” imagined Toyo.
When he next appeared before his teacher, Toyo imitated dripping water. “What is that?” asked Mokurai. “That is not the sound of one hand. Try again.”
Toyo meditated to hear the sound of one hand. He heard the sighing of the wind. But that sound was rejected by the master. He heard the cry of an owl. This also was refused. Neither were the locusts the sound of one hand. Toyo visited Mokurai with different sounds. All were wrong. And for almost a year he pondered what the sound of one hand might be.
“I collect no more,” he finally said, “I have reached the soundless sound.”
At last little Toyo entered true meditation and transcended all sounds. Toyo had realised the sound of one hand.
(Re-written from: Zen Koans)