ined, will be found in the Decision of the
basic problem. Suppose the Decision in this case to have been "to
destroy the enemy convoy". The task thus determined for the subsidiary
problem becomes an assigned task in the sense that it is assigned by
the commander to himself, instead of to a subordinate; however, it is
also an assigned task in the sense that it has been indirectly
assigned by the immediate superior, because it has been derived, in
the basic estimate, from the motivating task which was directly
assigned by the superior.

The two elements, of task and purpose, when linked together, enable
the commander to visualize the appropriate effect desired, as the
basis for his subsidiary estimate,--a procedure identical with that
followed in a basic estimate. As in the latter, the commander can now
formulate his subsidiary mission, as:--

(Task) To destroy the enemy convoy,

(Purpose) in order to prevent it from reaching its
destination.

The mission of the subsidiary problem is thus seen to be identical
with the basic Decision linked to the purpose of that Decision.

However, this is not always the case. A subsidiary problem may merely
involve the execution by the commander, i.e., under his own immediate
direction, of a designated part of his general plan. Or, such a
problem may involve execution, by the commander, of one or more of the
detailed operations for the accomplishment of his general plan or of a
part thereof. The commander may also find it necessary to solve
numerous subsidiary problems of relatively restricted scope pertaining
either to his general plan or to a part thereof or to the detailed
operations involved.

In some of these cases the purpose of the subsidiary mission may be
readily apparent. In others, its nature may become clear only after
the application of considerable mental effort. In every case the
determination of a proper (subsidiary) purpose involves visualization
of a situation which the commander desires to bring about or to
maintain. The (subsidiary) task, appropriate to the (subsidiary)
purpose, will always necessarily be suitable to the latter. This task
is then the motivating task for the solution of the particular
subsidiary problem in hand. This will be the case whether the
commander makes a simple mental solution or produces a more complex
one in which the formal written estimate of the situation is employed.
In the former instance, the brevity of the mental p