Retreat is in the category of defence and is a continuation of defence, while pursuit is a continuation of attack. It should be pointed out that destruction of the enemy is the primary object of war and self-preservation the secondary, because onlv by destroying the enemy in large numbers can one effectively preserve oneself. Therefore attack, the chief means of destroying the enemy, is primary, while defence, a supplementary means of destroying the enemy and a means of self-preservation, is secondary. In actual warfare the chief role is played by defence much of the time and by attack for the rest of the time, but if war is taken as a whole, attack remains primary. Selected Works, Vol.
Every war exacts a price, sometimes an extremely high one.
All technical principles and all principles concerning tactics, campaigns and strategy represent applications of this basic principle. The principle of preserving oneself and destroying the enemy is the basis of all military principles. Holding or seizing a city or place is the outcome of wiping out the enemy's effective strength, and often a city or place can be held or seized for good only after it has changed hands a number of times. In special circumstances, use the method of dealing the enemy crushing blows, that is, concentrate all our strength to make a frontal attack and an attack on one or both of his flanks, with the aim of wiping out one part and routing another so that our army can swiftly move its troops to smash other enemy forces. Strive to avoid battles of attrition in which we lose more than we gain or only break even.