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.

The nearer the cutting off point lies to the main force of the enemy, the more immediate the effect; whereas the closer to the strategic base it takes place, the greater the effect.

The military weapon is but one of the means that serve the purposes of war: one out of the assortment which grand strategy can employ.

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.

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.

If you find your opponent in a strong position costly to force, you should leave him a line of retreat as the quickest way of loosening his resistance. It should, equally, be a principle of policy, especially in war, to provide your opponent with a ladder by which he can climb down.

The practical value of history is to throw the film of the past through the material projector of the present on to the screen of the future.