bīng guì shèng, bù guì jiǔ 兵贵胜，不贵久
In War, Seek Quick Victory, Not Prolongation.
Warfare should seek a quick victory and should not be prolonged. This was a principle of warfare proposed by Sunzi, the ancient military strategist. It is of particular importance to the party that initiates a war. If the war continues without a decisive outcome, it will result in poor morale, weakened combat ability, an increase in various types of consumption, and difficulty in maintaining supply lines. Ultimately it will be hard to achieve the aims of the war and losses may even exceed gains; complications may also ensue which endanger the country’s security. This is a comprehensive concept of war which incorporates political, economic and other factors.
The crux of war is gaining a victory. Hence prolonged warfare tires the troops and saps their morale; they will be thwarted when attacking cities; if they are deployed away from home for a long time, the country’s finances will be in difficulty… Hence warfare should seek quick victory and not prolongation. Thus a commander who is skilled in warfare controls the destiny of his people and is master of his country’s security. (The Art of War)