The “T” trench has many more advantages than the few mentioned in the opening of this chapter. T fire-bays may be single, double or treble (that is with one, two or three bays). Fire-bays in any length up to 15 feet with 8 feet traverses are for firing purposes only, and the control trench, sometimes known as the lateral communication trench, as its name implies, giving lateral communications, is used for that purpose only. Therefore, the fire-bays and control trenches can be narrower than trenches which have to be used for both purposes, thus lessening the amount of repair and revetment work required. And the intervening ground between these fire-bays gives the same result as a traverse used in a traversed trench system, and saves the labor of digging a more intricate system. The control trench gives an officer or N. C. O. in charge of the T bays a chance to handle his men and fire in these bays without struggling around innumerable traverses and wasting time very often when a minute lost or gained means lives lost, or part of a trench system in the hands of the enemy. T bays may be sited with due and careful consideration while facing the enemy in an existing trench system. Thus it gives you the advantage of being able to take into consideration all the requirements of the field of fire, control of isolated areas, and the obtaining of maximum results from enfilade fire. These T trenches may be dug out from the old system without undue exposure of your men and if distance between the lines permits, and it is entirely possible to construct a new and generally more favorable line of trenches within 100 to 200 yards of the enemy’s trenches. Intervening ground between these T bays must be completely controlled by entanglements and mobile machine guns, or automatic rifles, able to operate from different alternating recesses in the control trench. Fire platforms should be placed in recesses at intervals in the control trench from which covering fire can be given. Artillery fire, to damage a T trench, must be very accurate. In a traversed trench a shell destroys not only lateral communication, but the defenders as well, whereas with a T shape, both fire-bays and control trench have to be ranged and hit. The success of the enemy is entirely local when capturing one of these T-bays, and he may be shelled by your own artillery without any danger or risks to those defending their T-bays. Control trenches should be dug first and zigzagged with the longer stretches facing the enemy. This gives you another fire-trench as well as a communication trench, and is also ready for use at any time needed before the T-bay is completed. On the completion of the T-bay, the corners of the zigzagged trench must be rounded off to make it easier and quicker for the movement of troops and carrying of stretchers. DUGOUTS