nders.

7. The relieving commander then inspects his trenches. He
ascertains that all his watchers are at their posts and that
the balance of his men know their posts and duties and are
prepared to assume them quickly.

8. The duties of the relieved commander are:
(1) To turn over his sector thoroughly policed and in good
condition as regards its construction and the new work,
if any, in progress.
(2) To turn over his supplies in good condition and fully
accounted for.
(3) After reporting the relief, to march his men back to
billets as promptly and secretly as possible, in column
of files, platoon leaders in the rear of their platoons,
a non-commissioned officer and guide at the head of each.
(4) On the evening preceding relief, to send his cooks back
to billets so that his men may be provided with a hot
meal immediately on arrival.

D. If an attack occurs during the march through the boyaux, to or
from relief, the company affected occupies the nearest
defensive position and at once notifies its battalion
commander. If an attack occurs during the actual process of
relief, the senior officer present takes command.

II. The Stay in the Trenches.

A. THE FOUR OBJECTS OF A TRENCH COMMANDER:

1. Security of his sector.
2. Protection of his troops.
3. Constant and accurate observation.
4. A continuous offensive.

B. HIS PLAN OF DEFENSE:

1. General principles of defense:
(a) Arrangement in depth. The most dependable defense is in
prearranged counter attacks. The system of defense must
react like a helical spring.
(b) Tenacity of defense.
1. Each unit must be prepared to hold its post to the last
extremity.
2. Orders to withdraw will never be obeyed unless
unmistakably valid.
3. All ground lost must be retaken at once in counter attack
by the unit which lost it.
(c) Apportionment of responsibility. Each active segment must
have a commander responsible for its defense, upkeep and
sanitation, and the discipline and instruction of his men.

2. Basis:
(a) The plan of defense turned over by the preceding commander.
This will usually suffice fo