Alphabetical Order:O
- Odachi, Shigeo(1892-1955)
- Oe, Taku(1847-1921)
- Ogata, Taketora(1888-1956)
- Ogino, Ginko(1851-1913)
- Ogiwara, Morie(1879-1910)
- Oguchi, Kiroku(1870-1957)
- Ogura, Masatsune(1875-1961)
- Oguri, Tadamasa(1827-1868)
- Ohigashi, Gitetsu(1842-1905)
- Oi, Kentaro(1843-1922)
- Oishi, Buichi(1909-2003)
- Okada, Keisuke(1868-1952)
- Okada, Ryohei(1864-1934)
- Okada, Tadahiko(1878-1958)
- Okano, Keijiro(1865-1925)
- Okawa, Heizaburo(1860-1936)
- Okawa, Shumei(1886-1957)
- Okazaki, Kunisuke(1853-1936)
- Okazawa, Kuwashi(1844-1908)
- Oki, Enkichi(1871-1926)