WA — Harmony
KEI — Respect
SEI — Purity
JAKU — Inner tranquility transcending individual desire
Rikyu believed that there were four principles fundamental to Tea:
Calligraphy by Onozawa Kankai
By emphasizing these principles, he firmly established the preparation of tea as a hoben, one of the many "skillful means" by which a practitioner of Zen might attain enlightenment.