rate,
subsidiary estimate with respect to the determination of the stages of
his operation, including the details as to the performance of the
first stage. In this case he finds a proper mission for his subsidiary
estimate in the basic Decision, linked to its purpose. This mission
would be as follows:--

(Task) To deny the enemy the use of base sites within
effective bombing range of A,

(Purpose) in order to protect the base at A.

During the subsidiary estimate the commander may discover, in his
study of the area ABCD, the necessity for an operation to deny Y
island to the enemy, and may even go so far, in this study, as to
decide on the capture of this island. The decision, settling on this
area as the scene of the first stage of his effort, may then include
provision for the capture of the island, as follows:

Decision: To deny the enemy the use of base sites in the area
ABCD as a first stage toward denying him the use of all base
sites within effective bombing range of the base at A.

Corollary: To capture Y island.

However, the commander may not take up the matter of denying Y island,
specifically, to enemy use until he studies the detailed operations
required for the accomplishment of the action involved in his first
stage. In such event, he may make provision for the capture of the
island in his subsidiary plan for the execution of the first stage. He
may find, on the other hand, that he prefers to make a separate,
subsidiary estimate as to this feature. If so, the mission for this
subsidiary estimate would be identical with the decision (less the
corollary, but plus the purpose of the estimate), i.e.,--

(Task) To deny the enemy the use of base sites within
effective bombing range of the area ABCD as a first stage

(Purpose) toward denying him the use of all base sites within
effective bombing range of the base at A.

During this estimate the commander considers the various courses of
action whereby he can deny to the enemy all bases in the area of the
first stage. Concluding that Y island is the only base site not
securely in friendly hands, and that the best method of denying it to
the enemy is to capture it himself, he reaches a decision as follows:

Decision: To capture Y island, in order to deny to the enemy
the use of the only available base site in the area ABCD.

In each of the foregoing cases, the commander is said to have
"deduced" the