Kiyozawa Manshi (清沢 満之; 1863–1903) was a Japanese Shin Buddhist thinker, academic and reformer of the Ōtani-ha branch. He is one of the most influential figures of Shin Buddhist modernism, known for his articulation of the philosophy of Seishinshugi (精神主義), which can be translated as “Cultivating Spirituality.” Seishinshugi thought prioritized personal religious experience and was influenced by Western philosophies like religious existentialism, Hegel and Stoicism.
Source: “Kiyozawa Manshi”, English Wikipedia (CC BY-SA 4.0), excerpt