Budō ('武道', lit. 'way of war') is the collection of Japanese martial arts that describe themselves as a dō - a way or path. Budō distinguish themselves in comparison to bujutsu - martial arts which do not encompass a philosophy that encourages their practitioners to live according to certain principles, as is the case in budō.
Historically, budō was literally the way of war and concerned itself with the realities of conflict and death. Although these have ceased to be such immediate realities for most modern budōka, budō still concerns itself with its original sense of conquering oneself and the resolution of internal conflict. Budō is thus a means of self-refinement and the development of one's character, and this is the principal aim of modern budō.
There are two main classifications of Japanese martial art. Arts which were established prior to the Meiji Restoration of 1868 are classified as koryū ('old schools'), and arts established subsequently to this event are classified as gendai budō ('modern budō').
Examples of gendai budō include aikidō, iaidō, jōdō, kendō and judō. These budō often inherit from bujutsu that went before them, and the examples previously given respectively inherit from aikijūjutsu, iaijutsu, jōjutsu, kenjutsu and jūjutsu.
Bujutsu are not necessarily koryū, as there can be modern bujutsu, however the distinction between bujutsu and budō lies in that bujutsu are at their core concerned with defeating external opponents (and without rules or ethical considerations), whereas gendai budō are not, and often do concern themselves with ethical philosophies. Gendai budō often incorporate competitive elements, but these are a means to bettering oneself and are not the life-or-death scenarios that bujutsu assumes. Rather than the external opponents, the opponent in gendai budō is usually considered to be one's own ego.