and their lord, and were trained as officers in military tactics and grand strategy. While these samurai numbered less than 10% of then Japan's population, their teachings can still be found today in both everyday life and in modern Japanese martial arts. History Asuka and Nara periods Following the Battle of Hakusukinoe against Tang China and Silla in 663 AD, which led to a retreat from Korean affairs, Japan underwent widespread reform. One of the most important was that of the Taika Reform, issued by Prince Naka-no-Ōe (Emperor Tenji) in 646. This edict allowed the Japanese aristocracy to adopt the Tang dynasty political structure, bureaucracy, culture, religion, and philosophy. As part of the Taihō Code of 702, and the later Yōrō Code, the population was required to report regularly for the census, a precursor for national conscription. With an understanding of how the population was distributed, Emperor Monmu introduced a law whereby 1 in 3–4 adult males were drafted into the national military. These soldiers were required to supply their own weapons, and in return were exempted from duties and taxes. This was one of the first attempts by the imperial government to form an organized army modeled after the Chinese system. It was called "Gundan-Sei" (:ja:軍団制) by later historians and is believed to have been short-lived. The Taihō Code classified most of the Imperial bureaucrats into 12 ranks, each divided into two sub-ranks, 1st rank being the highest adviser to the emperor. Those of 6th rank and below were referred to as "samurai" and dealt with day-to-day affairs and were initially civilian public servants, in keeping with the original derivation of this word from , a verb meaning 'to serve'. Military men, however, would not be referred to as "samurai" for many more centuries. Heian period In the early Heian period, during the late 8th and early 9th centuries, Emperor Kanmu sought to consolidate and expand his rule in northern Honshū and made military campaigns against the Emishi, who resisted the governance of the Kyoto-based imperial court. Emperor Kanmu introduced the title of sei'i-taishōgun (), or shōgun, and began to rely on the powerful regional clans to conquer the Emishi. Skilled in mounted combat and archery (kyūdō), these clan warriors became the emperor's preferred tool for putting down rebellions; the most well-known of which was Sakanoue no Tamuramaro. Though this is the first known use of the title shōgun,