This cover design was created for the One Drop Zen Community and the Angkor Verlag/Publisher.
The calligraphy is made by Shodo Harada Roshi and means "Mind/Heart" ("Shin/Kokoro" in Japanese, "Geist" in German).
The book contains Shodo Harada Roshi's commentaries on Sansokanchi Zenji/Sengcan's teaching of "On believing in mind".
Shodo Harada Roshi (原田 正道, Harada Shōdō, c. 1940) is a Rinzai Zen master, priest, author, calligrapher, and head abbot of Sōgen-ji — a three-hundred-year-old temple in Okayama, Japan. He has monasteries and teaches regularly in Europe (Hokuozan Monastery), in America (Tahoma Monastery) and in India (Indozan Monastery) as well.
You can buy the book here: https://bit.ly/2P28I0T