运用之妙，存乎一心

Explanation: Means gracefully battle after battle, it is conventional war, but the clever use of a flexible, full is good at thinking. Means the superb art of battle command. 　　Usage: Complex sentence; for adverbial; for war 　　Source: "Song Shi Yuefei Biography" record, said Yue Fei of the array and then Zongze war, military science often, the use of the wonderful, Bottom of Heart. " 　　Examples: The ancients called ~ ", this wonderful", we call flexibility, it is wise commander of the product. ★ Mao Zedong's "On Protracted War"