While there are many causes for which a state goes to war, its fundamental object can be epitomized as that of ensuring the continuance of its policy - in face of the determination of the opposing state to pursue a contrary policy. In the human will lies the source and mainspring of conflict.

For if we merely take what obviously appears the line of least resistance, its obviousness will appeal to the opponent also; and this line may no longer be that of least resistance. In studying the physical aspect, we must never lose sight of the psychological, and only when both are combined is the strategy truly an indirect approach, calculated to dislocate the opponent's balance.

An army should always be so distributed that its parts can aid each other and combine to produce the maximum possible concentration of force at one place, while the minimum force necessary is used elsewhere to prepare the success of the concentration.

This high proportion of history's decisive campaigns, the significance of which is enhanced by the comparative rarity of the direct approach, enforces the conclusion that the indirect is by far the most hopeful and economic form of strategy.

It should be the aim of grand strategy to discover and pierce the Achilles' heel of the opposing government's power to make war. Strategy, in turn, should seek to penetrate a joint in the harness of the opposing forces. To apply one's strength where the opponent is strong weakens oneself disproportionately to the effect attained. To strike with strong effect, one must strike at weakness.

In the case of a state that is seeking not conquest but the maintenance of its security, the aim is fulfilled if the threat is removed - if the enemy is led to abandon his purpose.

The effect to be sought is the dislocation of the opponent's mind and dispositions - such an effect is the true gauge of an indirect approach.