In the second phase of the siege the machine guns not required for the outpost line should be allotted to the local reserves and the general reserve, and will be used as circumstances require in assisting attacks on outlying works and in repelling counter-attacks. In the third phase machine guns must be pushed up to secure sap-heads and to assist the infantry in the assault; they will be found specially useful in covering the advance of assaulting infantry by sweeping parapets with fire and in securing captured works against counter-attacks. Sandbags should always be carried with machine guns supporting infantry in the assault, and the first consideration should be to secure the guns from fire on reaching a position. It must be remembered that machine guns in siege operations are always exposed to their worst enemy--artillery--and that their only hope of success is by concealment and cover. An example of their use in repulsing a counter-attack at Port Arthur is given by Nojine in his book _The Truth about Port Arthur_. Speaking of the attempt by the Russians to retake Chien-shan, he says: “The 13th Regiment took two-thirds of it, but could not advance further, as the Japanese threw in heavy reinforcements _and brought up a number of machine guns_. On the night of the 5th we had to withdraw and abandon further attempts to retake the position, as one attack alone had cost us 500 men.” The following account from the U.S.A. Official Report of the storming of Fort Erh-lung, one of the principal forts of Port Arthur, shows how machine guns can be used to assist in the final assault. “On December 28th the parapet of Fort Erh-lung was blown up at 10 a.m. by five mines being simultaneously sprung.... When the smoke cleared sufficiently, the exterior slope at the salient of the fort was seen to be filled with a dense crowd of Japanese infantry, who closely hugged the ground.... It appears that the Russians had occupied the heavy gun line which lies in the interior of the fort _and with machine guns_ raked the front parapet and thus made it impossible for the Japanese infantry to leave their cover on the exterior slope. Meanwhile the Japanese brought up _three machine guns, and with these replied to the Russian fire from the heavy line_.... The bombardment kept up without diminution until about 1 p.m., when it slackened perceptibly on both sides.... About 4 p.m. the Japanese infantry could be seen working along the flanks of the work on the outside of the parapet. The Russians retired to the gorge parapet which had been arranged to fire to the front, and maintained themselves for several hours longer. By 7.30 p.m. the Japanese had fully mastered the position, and the largest and strongest of the permanent works on the front of attack fell into their possession.... A large number of field and machine guns[49] were included in the spoils of Fort Erh-lung. The assault entailed a loss of about 1,000 men to the Japanese.”