He led the second successful attempt in 1977 to reach the summit of K2 and several other Japanese expeditions. Yoshizawa became a member of the Japanese Alpine Club in 1925 and later also a member of the American Alpine Club.
Yoshizawa successfully climbed K2 twice, with his first attempt being successful in 1977. He was also involved in several other Japanese expeditions. Yoshizawa joined the Japanese Alpine Club in 1925 and later became a member of the American Alpine Club.