To assess oneself and the enemy and make decisions based on predictions means planning before the war.

The entire military thought of Sun Tzu serves as an outline. Cao Cao said: "The strategist selects generals, measures the enemy, measures the territory, predicts soldiers, and dangers far and near, and plans in the temple." Ji, literally translated as calculation, calculation (comparison), plan, etc., here refers to strategic planning.

That is, before the war begins, the emperor and his ministers must first plan in the temple, analyze the strengths and weaknesses of the enemy and ourselves, compare the gains and losses of the war, predict the outcome of the war, and then formulate a war plan, stipulate strategic and tactical principles, and use the war as a guide. victory.

Plan first and then fight is the basic principle of military use. To fight, you must first have a mature strategy and then put it into practice. Therefore, Sun Tzu opened the book on "strategy" as the first of the thirteen chapters.

It studies and plans the importance of war from an overall strategic perspective, explores the basic conditions that determine the outcome of a war, and puts forward the war decision-making thought of "taking the plan by the school" and the military saying of "surprise the unexpected and attack the unprepared". .