THE CASE: The priest Jui-yen called “Master!” to himself every day and answered himself “Yes!” Then he would say “Be aware!” and reply “Yes!” “Don’t be deceived by others!” “No, no!”" (from "The Gateless Barrier: The Wu-Men Kuan (Mumonkan)" by Robert Aitken)

This is good practice for everyday life. He is basically calling out the name Master! And the key is the effortless immediacy of the response – YES! That YES is everything. What is he saying Yes too? Who is the Master?