The endemic เฉพาะถิ่น wars between the various states at that time caused Sun Wu to think deeply about military strategy through a lot of effort. He wrote “The Art of War”, and presented it to the ruler of Wu, who put him in command บัญชาการ of his army. He imposed กำหนด strict discipline ระเบียบวินัย on the army and he was very conscientious ตั้งในทำสิ่งดี in training troops. In consequence, Wu soon became a major military power in the Spring and Autumn Period.