moved south through mountainous terrain , reaching the hamlet of Bianyupusa on 8 October. Kuropatkin gambled that Ōyama would perceive that the Western Detachment moving down the plains was the main thrust against Liaoyang, whereas his main strike force was actually the Eastern Detachment moving in the concealment of the hills. The ruse initially worked, and Ōyama was reluctant to accept General Kuroki's assessment of the true situation until a copy of Kuropatkin’s written orders to General Stakelberg were discovered on the body of a Russian officer killed in a skirmish on 9 October. On 10 October, Ōyama ordered a major Japanese counter-offensive aimed at the center of the Russian line. The Japanese battle plan was to use Kuroki’s IJA 1st Army to pin down Stackelberg’s forces while striking hard against Bilderling’s Western Division with IJA 2nd and IJA 4th Armies in flanking maneuvers before Kuropatkin could bring it up to full strength. The Russians suffered heavy casualties in the east and were pushed back in the west, forcing Kuropatkin to commit part of his reserves into a Central Detachment to fill in the gap created. This Central Detachment was made from the First European Army Corps and Fourth Siberian Army Corps. The IJA 4th Division successfully turned the Russian right flank on 11 October, forcing Bilderling to retreat further. On the left flank, Stackelberg attacked the IJA 12th Division near the Yantai coal mines, and by nightfall had taken 5000 casualties. The IJA 12th Division had lost even more men, but held its ground. On 12 October, Ōyama ordered Prince Kan'in Kotohito's IJA 2nd Cavalry Brigade against the Russian left flank. The Russians were forced back on the left flank as well. Russian operations were hampered by Kuropatkin's distrust of his generals, and often dispatched orders directly to their subordinates without informing Stackelberg or Bilderling. He also refused to use the field telephone system, so the orders often took several hours to reach their destination by courier. On the south bank of the river was a small ridge called Sankaiseki-san ("Three Rock Hill") by the Japanese. Although only 100 feet tall, it commanded a wide view of the plains south of Mukden and was regarded as strategically important by the Russians, who had occupied it on 9 October. On the night of 12 October, the IJA 10th Division made a night assault and had taken the hill by early