During the Russo-Japanese War, "Chōkai" assisted in the Siege of Port Arthur. During the third attempt to sink old freighters in an attempt to block the entrance to Port Arthur harbor, "Chōkai" was present as one of the escorts. On a shore bombardment mission on 26 May 1904 to support the Japanese Second Army at the Battle of Nanshan (together with the cruiser ), "Chōkai" came under fire, and her captain, Lieutenant Commander Hayashi Michio was killed. He was replaced by Lieutenant Commander Hirose Katsuhiko, the older brother of the famed war-hero Takeo Hirose, who commanded "Chōkai" through the end of the war, including the Invasion of Sakhalin towards the end of the war.