Be that as it may, it is necessary to realise the difficulties to be faced, not the least of which is the question of _training_, for, as already pointed out, it is absolutely essential to the successful use of machine guns that the personnel should be very highly trained, and this applies to their use in enclosed country even more than elsewhere. Although as a general principle enclosed country benefits the attacker and is disadvantageous to the defender, this is not always the case with machine guns, and provided the golden rule of “concealment, cover, and surprise” is intelligently applied, enclosed country is particularly suited for the use of machine guns in the defence. For this purpose machine guns should be trained to work in pairs in mutual support. They must be so mounted that they can be carried by hand for considerable distances into position, and must be capable of firing from a low siting when they must be inconspicuous. If mounted, as at present, on a wheeled carriage, a light tripod may be carried on the carriage, which will render the gun far more inconspicuous and useful. While all the principles for the tactical handling of machine guns with infantry hold good, there are several points of importance to be noted in using them in the defence in enclosed country. The advance of any formed bodies of the enemy will be confined to the roads; consequently machine guns must endeavour to command all roads leading from the enemy, especially where they become defiles.