Ostasiengeschwader
"Yahagi" participated in World War I as part of Japan's contribution to the Allied war effort under the Anglo-Japanese Alliance. She was in the Japanese squadron which gave chase to the German East Asia Squadron led by Admiral Graf Maximilian von Spee in 1914. "Hirado" and "Yahagi" were in the Allied 2nd Southern Squadron led by the battleship and commanded by Rear-Admiral Matsumura Tatsuo, patrolling the region around Sumatra unsuccessfully for the German cruiser .