One day when Nangaku came to Basso’s hut, Basso stood up to receive him. Nangaku asked him, “What have you been doing recently?”
Basso replied, “Recently I have been doing the practice of seated meditation exclusively.”
Nangaku asked, “And what is the aim of your seated meditation?”
Basso replied, “The aim of my seated meditation is to achieve Buddhahood.”
Thereupon, Nangaku took a roof tile and began rubbing it on a rock near Basso’s hut.
Basso, upon seeing this, asked him, “Reverend Monk, what are you doing?”
Nangaku replied, “I am polishing a roof tile.”
Basso then asked, “What are you going to make by polishing a roof tile?”
Nangaku replied, “I am polishing it to make a mirror.”
Basso said, “How can you possibly make a mirror by rubbing a tile?”
Nangaku replied, “How can you possibly make yourself into a Buddha by doing seated meditation?”
– zen story