Some clans were originally formed by farmers who had taken up arms to protect themselves from the imperial magistrates sent to govern their lands and collect taxes.[citation needed] These clans formed alliances to protect themselves against more powerful clans, and by the mid-Heian period they had adopted characteristic Japanese armour and weapons, and laid the foundations of Bushido, their ethical code.[citation needed]

Samurai warriors described themselves as followers of "The Way of the Warrior" or Bushido. Bushidō is defined by the Japanese dictionary Shogakukan Kokugo Daijiten as "a unique philosophy (ronri) that spread through the warrior class from the Muromachi (chusei) period. From the earliest times, the Samurai felt that the path of the warrior was one of honor, emphasizing duty to one's master, and loyalty unto death.[4]

In the 13th century, Hojo Shigetoki (1198-1261 A.D.) wrote: "When one is serving officially or in the master's court, he should not think of a hundred or a thousand people, but should consider only the importance of the master."