Koorn River without the
previous occupation of that defile, and all the wagons were captured.
This not only emphasises the necessity for an Advanced Guard in
retreat, but points to the need of tactical knowledge on the part of
the Rear Guard commander, especially in mountainous country or in
terrain cut up by woods and marshes, where the train is liable to cause
delays, as the withdrawing force is compelled to march in a long drawn
column. Extra time must be gained by the Main Guard to enable the Main
Body to emerge from the defile. The Rear Guard commander must
therefore adapt his plans to suit the country through which the Main
Body has to pass, as well as the country in which he will himself fight
Delaying Actions. A good map and ability to use it, and close
co-operation with the Main Body, must be determining factors for
success or failure.

TRAINING.--When troops are being exercised in Rear Guard work
opportunities should be taken to explain the difficulties of choosing
suitable positions, of withdrawing from them when involved in battle,
of the paramount necessity for mutual support, and of accepting {125}
any risk that may be required to safeguard the Main Body. Stress
should be laid upon the importance of Fire Tactics (the judicious
combination of Fire and Movement), the greatest of all factors in a
successful Rear Guard battle, and upon the ability to read and
understand a map, an essential qualification in all movements of troops
and indispensable in Rear Guard fighting. From the map a platoon
commander must be able to predict the probable line of the enemy's
advance against the line of resistance as well as the best route to be
taken when, at length, he withdraws his platoon to another fire
position in rear; while he must be prepared to throw his platoon in
local counter-attack on the flank or rear of an assaulting party that
has become detached from its supports and therefore affords a fleeting
opportunity for a local fighting success, and a rapid advance for this
purpose along a route unseen to the foe, a speedy reorganisation after
victory, and a rapid withdrawal to the point of issue, or to a line in
rear, can best be achieved by use of the map and reconnaissance of the
ground of the encounter.

EYE FOR GROUND.--One of the secrets of Napoleon's extraordinary
successes was his "eye for ground." "It was not until I went to Jena
and Austerlitz that I really grasped what an important part an eye for