In bringing machine guns into action for this purpose, they will generally be used in batteries, but may come into action in sections or even single guns once the objective has been pointed out. The object being to obtain superiority of fire regardless of cost, rapidity and concentration of fire must be the principal points. The guns must therefore press forward to the closest range, and where it is possible to bring a cross or enfilading fire to bear, the opportunity must not be neglected. It may be necessary to fire over the heads of the infantry or even to push guns into the firing line itself, though this is seldom desirable if good positions can be found in rear. When any portion of the line advances to the assault, fire must be concentrated over their heads on the position assaulted; and when they are so close to the position as to render such fire impossible, fire must not cease, but be directed over the position so as to strike the enemy as they retreat. Fire from machine guns may be kept up from 500 yards’ range over the heads of prone infantry within 100 yards of the target with perfect safety, and from 800 yards over infantry advancing to within the same distance. General Nogi, speaking of the use of machine guns in the attack, says: “Our troops trained machine guns on the most advanced lines of infantry _to overwhelm with fire the points at which resistance was greatest_. Sacks of earth were used to mask them. _They have often enabled the infantry to advance with success._” M. Ullrich, war correspondent of the _Gazette de Cologne_, was present in many engagements in which machine guns were pushed up to support the firing line in the final stage. He says: “In the offensive the Japanese frequently made successful use of machine guns. _When the infantry were carrying out a decisive attack, they were supported by their machine guns, which concentrated their fire on points arranged beforehand_.... When machine guns have been skilfully employed, their action has been infinitely more effective than that of field artillery, more especially when they fire at infantry ranges.” The following is an example of their actual use in this way. “The Japanese,” says a Russian eye-witness of the fighting round Mukden, “brought up during the night dozens of machine guns with hundreds of thousands of cartridges to their front line of skirmishers, from 400 to 500 yards from our positions, and entrenched them there. _When the assault commenced, at dawn, the machine guns opened fire with fatal accuracy on the parapets of our trenches and on our reserves_, preventing them from coming up. We could do nothing with the enemy, because when the machine guns showed the least vulnerability, they were at once protected by shields of bullet-proof steel.”[23]