From Matsuyama domain, Iyo Province (Ehime Prefecture), Akiyama Saneyuki was the younger brother of Army Lieutenant General Akiyama Yoshifuru. He graduated top of his class from the Naval Academy, then studied in the United States where he learned Alfred Mahan's naval strategic theory directly. After returning to Japan, he devoted himself to establishing tactical and operational education for the navy and is called the "Father of Japanese Naval Tactics." In the Russo-Japanese War he served as operations staff officer of the Combined Fleet and drafted the entire operational plan for the Battle of Tsushima. He is credited with composing the famous telegrams "Enemy fleet sighted" and "Weather fine, but waves high." He continued as a staff officer until the Combined Fleet was disbanded, contributing greatly to Japan's victory. In his later years, despite illness, he devoted himself to writing and mentoring the next generation, dying of disease at age 49 in 1918. He is widely known alongside his brother Yoshifuru as one of the protagonists of Shiba Ryotaro's novel "Clouds Above the Hill." A rare military man who combined sharp strategic intellect with a poetic sensibility, he is remembered as an embodiment of the ideal of "excellence in both culture and martial arts."

Possessed a genius strategic mind but was also known for eccentric behavior—called the "oddball staff officer." Turned to religion in later years. His contrasting relationship with brother Yoshifuru is a key attraction of "Clouds Above the Hill."

Regarded as the strategist who contributed most to victory at Tsushima. "Clouds Above the Hill" is one of Japan's most beloved historical novels, adapted by NHK. Also a major tourism draw for Matsuyama.