On the staff of Yasutsura Genbansuke, a minister of Hojo Yasutoki, was one Morikatsu who was a nyudo student of Zen. Once when he came to Enkakuji he met one of Bukko’s attendants named Isshin, and said to him:
‘That stupid crowd at Kamakura don’t know how to write the name of our sect with the proper character, but get it mixed up with the character for “loin-cloth”. They’re an odd lot.’
The attendant was distressed that people should thus casually degrade the word Zen, and mentioned the matter to the teacher, who laughed and said:
‘Loin-cloth is indeed the great concern of our Zen gate, and those Kamakura soldiers must not be condemned for lack of learning. What gives the life to men is the power of the front gate (of men and women), and when they die, it ends with the (excretion at the) back gate. Is not this life-and-death the great concern of our Zen gate? And what contains the organs of life and death is the loin-cloth. If you penetrate into that which contains both, you will know where life comes from and where death goes to. Now use the loin-cloth to demonstrate our teaching to that little bit of an idiot, and get him to try to find out how it is when the loin-cloth is annihilated.’
Isshin went and brandished a loin-cloth before Morikatsu’s face, saying: ‘All living beings are wriggling about within the loin-cloth. When you annihilate the loin-cloth, how is it?’
Morikatsu had no words.
This began to be used as a koan in Kamakura Zen with Kosen, the 38th master at Kenchoji.