 The Russians were revitalised by the arrival of Admiral Stepan Makarov and were able to achieve some degree of success against the Japanese, but on 13 April Makarov's flagship, the battleship , struck a mine and sank; Makarov was among the dead.His successors failed to challenge the Japanese Navy, and the Russians were effectively bottled up in their base at Port Arthur.By May, the Japanese had landed forces on the Liaodong Peninsula and in August began the siege of the naval station.