|The Amur and Yenisei were assigned to the Pacific Fleet and based in Port Arthur when the Russo-Japanese War began. Two days after the February 8-
9, 1904 surprise Japanese naval attack on Port Arthur,Yenisei was in the process of laying a minefield at Dalian Bay when one of the mines somehow
broke loose and began floating towards the ship. While maneuvering to avoid the stray mine, Yenisei accidentally entered her own minefield and struck
another one. The explosion caused eight mines, that had not yet been deployed and still sitting of the rails, to detonate. Yenisei sank in 20 minutes with
the loss of about 100 crewmembers. The cruiser Boyarin, in the company of four destroyers, was sent to provide assistance and pick up survivors.
While responding to the accident, Boyarin herself fell victim to one of Yenisei’s mines. The explosion opened the hull and flooded the ship's machinery
spaces, which forced her crew to abandon ship. The cruiser remained afloat, but foundered in Dalian Bay the next day during a storm.
On May 14, 1905, Amur laid a field of 50 mines. The following morning, Rear Admiral Nashiba Tokioki led an Imperial Japanese Navy squadron
consisting of the battleships Hatsuse, Yashima and Shikishima to bombard Port Arthur. The squadron entered this minefield and Hatsuse and Yashima
both hit mines. Hatsuse first hit one mine which disabled her engines and steering, which caused her to drift and strike a second mine, detonating one of
her forward magazines. The ship sank in about 90 seconds, taking 496 men down with her. Yashima struck a mine as she maneuvered to avoid the
drifting Hatsuse, but she was towed away. However the damage was severe and the flooding could not be controlled, which forced her crew to abandon
her. Three hours after Yashima struck the mine she capsized and sank.
During the December 8, 1904 bombardment by Japanese artillery, Amur was struck several times while she was moored at a dock. The damage from
the 11-inch shells caused her to list at an angle of 68° at her moorings. Ten days later she was again hit a number of times during another artillery
bombardment and was sunk. The Japanese eventually raised her and she was scrapped.