Tenno achieved the rank of Zen teacher after 10 years of apprenticeship. He visited the famous Master Nan-in, who greeted him with a question about whether he left his shoes and umbrella on the porch and, if so, whether the umbrella was left to the left or right of the shoes. Tenno did not know the answer, realizing he lacked full awareness, so he studied under Nan-in for another 10 years to improve his mindfulness and attention to detail. The document encourages cultivating mindfulness through meditation practice, noting how lack of mindfulness can lead to problems while mindfulness brings calmness, joy and wisdom.