mission for his subsidiary problem. As has been
demonstrated, the process of deduction is merely the application of
the natural mental processes through the use of the estimate of the
situation. Whether the estimate is formal or informal, detailed or
brief, written or mental, is immaterial; in any case, the estimate
results in a decision which provides, with its purpose, a proper
mission for the succeeding problem which has been presented by
solution of its predecessors.

In logical sequence, from problem to problem, the procedure outlined
in the preceding discussion enables the commander to derive a correct
mission for the problem involving the capture of Y Island. Clear
visualization of such a subsidiary mission is frequently of great
importance, and may be difficult unless the procedure has been
carefully traced from each problem to the next. In this particular
example, if the commander finds that the capture of Y Island is of
such a specialized and localized nature (page 170) as to call for a
formal estimate (as may frequently be the case in capturing a
well-defended island base), he will be especially desirious of
deriving a correct (subsidiary) mission as a basis for this estimate.
In this instance a correct mission would be:--

(Task) To capture Y Island,

(Purpose) in order to deny to the enemy the use of the only
available base site in the area ABCD.

This mission is identical with the decision, linked to its purpose, of
the preceding subsidiary problem.

* * * * *

Subsidiary problems relating to training (page 160), when solved by
the procedure distinctive of the first step, involve estimates of the
situation very similar to those explained previously (Chapter VI).

Section I-A of such a training estimate will include a summary of the
salient features of the existing situation, from the strategical or
tactical viewpoint, together with a statement of the salient features
of the operations to be carried out for which the projected training
is designed. The incentive will be found in a previous decision
calling for the operations which require the training to be given. The
assigned objective will be the making of adequate provision for
training appropriate to the projected operations. The (subsidiary)
mission will be:--

(Task) to provide appropriate training,

(Purpose) in order to contribute to freedom of action during
the operations contempla