In some Zen traditions a Dharma talk may be referred to as a teisho. However, according to Taizan Maezumi and Bernard Glassman, a teisho is "a formal commentary by a Zen master on a koan or Zen text. In its strictest sense, teisho is non-dualistic and is thus distinguished from a Dharma talk, which is a lecture on a Buddhist topic." In this sense, a teisho is thus a formal Dharma talk. Vietnamese master Nhat Hanh says the following about Dharma talks: