Master Eisai (d.1215), a Japanese monk who established the Rinzai school of Zen in Japan, is also credited with popularizing tea drinking, but mulberry may have been his real passion.
Eisai wrote "Drink Tea to Nourish Life" (Kissa yōjōki), a text that advocated tea consumption and one that is often cited today to demonstrate the close connection between tea, especially the tea ceremony, and Zen Buddhism.
However, Eisai has a lot to say about mulberry in the same book. He referred to mulberry as a "plant of the Buddhas and Bodhisattvas" due to its curative powers. He also included recipes for medicines using mulberry branches, wood, leaves, and berries. For example, he suggested that chewing on pieces of mulberry wood could freshen the breath. In Eisai's view, people who consumed mulberry gained protection against evil influences. Perhaps there was some psychological benefit to eating mulberry due to beliefs in its curative powers?
Today, students of Zen might drink tea to stay awake while meditating, but they might also heed Eisai's words and examine the power of mulberry to maintain physical and mental health.