first line of trenches overrun, tenaciously refused to retreat and held control of 174 Meter Hill despite severe and mounting casualties. On the following day, August 20, 1904, Tretyakov asked for reinforcements but, just as at Nanshan, none was forthcoming. With more than half of his men killed or wounded and with his command disintegrating as small groups of men fell back in confusion, Tretyakov had no choice but to withdraw, and 174 Meter Hill was thus overrun by the Japanese. The assault on 174 Meter Hill alone had cost the Japanese some 1,800 killed and wounded and the Russians over 1,000. The assaults on the other sections of the Russian line had also cost the Japanese heavily, but with no results and no ground gained. When Nogi finally called off his attempt to penetrate the Wantai Ravine on August 24, 1904, he had only 174 Meter Hill and the West and East Pan-lung to show for his loss of more than 16,000 men. With all other positions remaining firmly under Russian control, Nogi at last decided to abandon frontal assaults in favor of a protracted siege. On August 25, 1904, the day after Nogi's last assault had failed, Marshal Ōyama Iwao engaged the Russians under General Aleksey Kuropatkin at the Battle of Liaoyang. The siege Having failed in his attempts to penetrate the Port Arthur fortifications by direct assault, Nogi now ordered sappers to construct trenches and tunnels under the Russian forts in order to explode mines to bring down the walls. By now, Nogi had also been reinforced by additional artillery and 16,000 more troops from Japan, which partially compensated for the casualties sustained in his first assaults. However, the major new development was the arrival of the first battery of huge siege howitzers, replacing those lost when the transport Hitachi Maru, loaded with a battalion of the First Reserve Regiment of the Guards, was sunk by Russian cruisers on June 15, 1904. The massive 11-inch howitzers could throw a 227-kilogram (500.4-pound) shell over 9 kilometers (5.6 miles), and Nogi at last had the firepower necessary to make a serious attempt against the Russian fortifications. The huge shells were nicknamed "roaring trains" by the Russian troops (for the sound they made just before impact), and during their period at Port Arthur over 35,000 of these shells were fired. The Armstrong howitzers had originally been installed in shore batteries