507. Unless the difficulty of moving the troops into the position be great, most of the troops of the firing line are held in rear of it until the infantry attack begins. The position itself is occupied by a small garrison only, with the necessary outguards or patrols in front. 508. Fire alone can not be depended upon to stop the attack. The troops must be determined to resort to the bayonet, if necessary. 509. If a night attack or close approach by the enemy is expected, troops in a prepared position should strengthen the outguards and firing line and construct as numerous and effective obstacles as possible. Supports and local reserves should move close to the firing line and should, with the firing line, keep bayonets fixed. If practicable, the front should be illuminated, preferably from the flanks of the section. 510. Only short range fire is of any value in resisting night attacks. The bayonet is the chief reliance. (See Night Operations.) _COUNTERATTACK._ 511. The passive defense should be assumed only when circumstances force it. Only the offensive wins. 512. An active defense seeks a favorable decision. A favorable decision can not be expected without counterattack. 513. A passive defense in a position whose flanks are not protected by natural obstacles is generally out of the question. 514. Where the defense is assumed with a view to making a counterattack, the troops for the counterattack should be held in reserve until the time arrives for such attack. The defensive line should be held by as few troops as possible in order that the force for the offensive may be as large as possible. The force for the counterattack should be held echeloned in rear of the flank which offers it the greatest advantage for the proposed attack. 515. The counterattack should be made vigorously and at the proper time. It will usually be made: By launching the reserve against the enemy's flank when his attack is in full progress. This is the most effective form of counterattack. Straight to the front by the firing line and supports after repulsing the enemy's attack and demoralizing him with pursuing fire. Or, by the troops in rear of the firing line when the enemy has reached the defensive position and is in disorder. 516. Minor counterattacks are sometimes necessary in order to drive the enemy from important positions gained by him. _DELAYING ACTION._ 517. When a position is taken merely to delay the enemy and to withdraw before becoming closely engaged, the important considerations are: The enemy should be forced to deploy early. The field of fire should therefore be good at distances from 500 to 1,200 yards or more; a good field of fire at close range is not necessary. The ground in rear of the position should favor the withdrawal of the firing line by screening the troops from the enemy's view and fire as soon as the position is vacated.