rocess tends to
obscure this fact.

An example might occur in a situation where the commander has received
an order to "Protect the base at A". It is then supposed that, after
estimating the situation, he has reached the Decision "to deny the
enemy the use of base sites within effective bombing range of A", the
purpose of the Decision being, of course, "in order to protect the
base at A". The action required might then be undertaken in two
stages. The first stage might be confined to the area ABCD. If, then,
all available base sites in this area, except Y island, were already
securely in friendly hands, the commander would find it necessary to
make provision for an operation to deny the use of this island to the
enemy. If this operation is of such a nature that the commander
desires to execute it under his own direct control, instead of
assigning it to a subordinate, it presents a subsidiary problem which
the commander, himself, has to solve.

The commander has now determined the necessity of solving a subsidiary
problem relating to the accomplishment of a designated part of his
general plan. He has also determined the necessity of solving another
subsidiary problem presented by an operation pertaining to the first
stage of the accomplishment of his general plan.

Each subsidiary problem requires an estimate of the situation although
"the brevity of the mental process tends to obscure this fact" (page
172).

In making his basic estimate, the commander may have discovered the
need for these subsidiary estimates. In this case, he may have
included them in his estimate, as "estimates within the estimate"
(page 83), in his analysis of the operations involved in the various
courses of action which he considered. For instance, his basic
Decision may have included the capture of Y island, and he may have
covered this feature by a corollary to that Decision, as follows:

Corollary: As a first stage, to deny the enemy the use of
available base sites in the area ABCD, by capturing Y island.

However, the commander may not discover the desirability or need of
solving these subsidiary problems until the second step, when
resolving the basic Decision into the detailed operations required. In
this case, he might make due provision at that time for the operations
involved in the subsidiary problems. The mental procedure would be the
same in either event.

The commander may find, however, that he prefers to make a sepa