Tanzan Ishibashi (石橋 湛山, Ishibashi Tanzan; 25 September 1884 – 25 April 1973) was a Japanese journalist and politician who served as prime minister of Japan from 1956 to 1957.
Born in Tokyo, Ishibashi became a journalist after graduating from Waseda University in 1907. In 1911, he joined the Tōyō Keizai Shimpo ("Eastern Economic Journal") and served as its editor-in-chief from 1925 to 1946 and president from 1941. In the 1930s, Ishibashi was one of the few critics of Japanese imperialism, and became well known as a liberal economist. From 1946 to 1947, Ishibashi served as finance minister under Shigeru Yoshida. He was elected into the National Diet in 1947, but was purged for openly opposing the U.S. occupation policies; he returned to the Diet in 1952, after which he allied with Ichiro Hatoyama and served as his minister of international trade and industry. Ishibashi succeeded Hatoyama as prime minister in 1956, simultaneously serving as director of the Defense Agency, but resigned soon after due to ill health.
