In 1189, Yoritomo led a massive army (said to number 280,000) to destroy the Fujiwara of Oshu, who had sheltered his brother Yoshitsune. Yasuhira was betrayed by his own retainers and killed, ending the three-generation Oshu Fujiwara dynasty. This campaign gave Yoritomo military control over all of Japan, paving the way for his appointment as Seii Taishogun in 1192. He prayed for victory at shrines along the route, including Kagurazaka Wakamiya Hachiman.

On March 10, 1945, approximately 300 B-29 bombers firebombed downtown Tokyo, killing about 100,000 people and leaving 1 million homeless in a single night — one of the most destructive air raids in history. The May 25 raid devastated the Yamanote area including Shinjuku and Kagurazaka, destroying shrines like Kagurazaka Wakamiya Hachiman. Tokyo rose from the ashes in a remarkable postwar reconstruction.