Secrets and deep knowledge passed from a Noh practitioner to only one child. There are plays, performances and styles in each school which are treated as isshisōden. However, the arts are made up of the accumulation of various ideas, with even some simple things passed down from parent to child as isshisōden. In the world of Noh and kyōgen, there is a teaching that the proper person to whom to pass on knowledge must be selected carefully, even if this is not one’s own child. Zeami himself had some harsh words about this practice in his notes on Fushikaden: “Noh should not be passed on to the unskilled, even if this is one’s own child. Whether of one’s own family or not, the person must be worthy of carrying on the tradition.”