Japanese painter and illustrator (1887–1931)
 was a Japanese painter and illustrator, noted for his work in pioneering the Hanshinkan Modernism trend in "yōga" (Western-style) portraiture and nude painting in early 20th century Japanese painting.
Biography.
Koide was born in what is now the Shinsaibashi area of Chūō-ku Osaka. Interested in art from childhood, he studied "Nihonga" in elementary and middle school. In 1907, he applied to the western arts department of Tokyo School of Fine Art, but failed his entrance examinations, and was accepted into the Nihonga department instead. Although he was able to study under famed "Nihonga" painter Shimomura Kanzan, he was still drawn to oil painting. After graduating in 1914 he returned to Osaka and continued to paint and entered a "yōga"-style portrait group titled "N-Family" into the 1919 6th "Nikakai" (Second Division Society) Exhibition, where he won the Chōgyū Prize. This painting is now recognized by the Agency of Cultural Affairs of the Japanese government as an Important Cultural Properties of Japan. In the "Nikakai" exhibition of 1920 his portrait of the "Young Girl Omme" received the Nika Prize.
He received numerous commissions following these successes, and experimented with a variety of media, including painting on glass. From 1921–1922, he travelled to France, and established his atelier in Osaka in 1924. (This studio is now preserved at the Ashiya City Art Museum). In his later years, Koide was especially known for his nudes.
He died in Ashiya, Hyōgo in 1931.