We talk a lot about samurai at the Samurai Archives, needless to say. I think most of us take for granted what a samurai was, however. I've never been truly confident in my own off-hand definition of the term. So without further ado, what was a samurai? Whole books have been written on the nature and evolution of the samurai (see Farris and Friday, specifically), so one post will definitely not be sufficient to address this problem. These are my impressions after reading several sources (specifically Friday's Hired Swords, Farris' Heavenly Warriors, and Varley's Warriors of Japan), so specific page numbers won't be mentioned. I'm not pleased with the brainstorming laid out in this post, but it's a start towards better understanding the samurai class. If you disagree or have more to add, please discuss it in the comments section!
A samurai was just a warrior: an armored man who rode a horse, had two deadly, curved swords, battled ninja for honor, and followed Bushido.
If a samurai was just a warrior, then anyone who practiced violence and destruction for a living would be called a samurai. If so, then where is their Bushido code of ethics? First off, the Bushido code of ethics is waiting to be invented in the 17th--early 20th century. Secondly, there are historical documents that list the number of samurai in different periods of Japanese history. The numbers are very small: remember that the samurai only numbered less than 10% of the whole population of Japan. Therefore, something distinguished this small group of people known as "samurai" from other warriors. I won't delve into the following very deep, but the samurai fought with bow and arrow much longer than he did with his iconic katana, ninja was simply the term for a samurai on a secret mission (once over, he would return to his normal position of counting rice in the castle storehouse), and Bushido...well, I'm not going to even touch Bushido in this post.
The etymology of the noun "samurai" 侍 derives from the classical Japanese verb, "saburau", which means "to serve" or "to attend." By that token, the noun form means, "a servant" or "an attendant."
There were 9 court ranks in the ancient system. The 5th rank signaled entry into the aristocratic class. The samurai were typically of the 6th rank, which means that they would serve or attend (in both the bureaucratic and military sense) to those individuals who held higher court ranks (5th-1st). Therefore, the Western misconception that samurai were definitively male warriors can be dispelled. The samurai held a certain rank and ranged from assassins to wet nurses to paper-pushers.
The samurai in battle was lightly armored, rode a small horse, and shot a bow and arrow, carrying a sword at his or her side.
The samurai needed a source of income. Living in an agrarian society (where one can't eat aristocratic or military titles), their best bet was to deal directly with the land. They became "on-site landlords" (a term Dr. William Wayne Farris uses often) who 1) made sure the peasants farmed and 2) collected taxes.
If we define the samurai as simply a mounted archer, we can see their origins very early. We would also be forced to call a shipwrecked Chinese merchant who rode a rose and carried a bow a "samurai" as well. I believe we need to dig deeper.
The Kiso horse is indigenous to the Japanese archipelago. Decreasing greatly in number in the Yayoi period, horses didn't come back onto the scene until c. 450 AD when they were brought over (with equestrian gear such as horse armor, stirrups, etc...) from Korea. These Korean horses were used for riding and military purposes. The bow and arrow (even composite versions) are found in archaeological sites as early as the Jomon Period (c. 10,000-300 BC), in roughly the same form as that used by the warriors of the late Heian Period (12th century). Therefore, by viewing the samurai as mounted archers, we see a very early (after c. 450) development. This line of reasoning would suggest that (1) kofun held samurai remains; (2) samurai were involved in the excursions to the Korean Peninsula; (3) samurai were intricately involved in the Ritsuryo State and the Taiho military; and (4) simply evolved into the samurai of the medieval period.
The district magistrates, who came from locally notable families, were institutionalized into around 550 officials throughout the archipelago in the Ritsuryo State/Taiho system of the late 7th/early 8th century. These locally notable people were individuals skilled in the martial arts (the way of the bow and horse; kyuuba no michi). If ancient military aristocrats became the 8th century district magistrates, then the former horseriding warrior elite evolved into the later district magistrates and both were therefore samurai. If horseriding archers weren't samurai originally, then the district magistrates were the ones to evolve eventually into samurai .
As far as a local notable goes, there were approximately 9 district magistrates per province (66 total), yielding a national total of around 550. They were the network or apparatus through which the Chinese-style bureaucratic system controlled the peasants. It seems only natural that district magistrates, who brought together and led the local armies, for the court, could be called "samurai" in the 8th century.
The district magistrates were given large tracts of land. In light of this, the local notables were also landowners. They were landlords as well, who charged exorbitant interest to the peasants. They controlled local matters and regulated/administered the raising of horses.
Many of the poems in the Man'youshuu anthology were written by the district magistrates, which projects forward to the image of the later, learned warrior aristocrats of the Heian period.
Or were samurai none of the above, but simply military aristocrats? These military aristocrats were people like Fujiwara no Nakamaro, Fujiwara no Sumitomo, and Taira no Masakado (incidentally all rebels). These men may be termed military aristocrats or servants of the court. Perhaps the 8th century Nakamaro and Hirotsugu are too early to be called "military aristocrats" for they weren't of military families, but were nobles who revolted. Yes, they had military retinues in the capital, but they are best termed aristocratic "servants of the court." Not only are all servants of the court not of the 6th or 5th court rank, but they don't belong to military houses. This factor of lineage (also important in premodern Shinto and Buddhist transmission) is important because samurai, as a basic prerequisite, placed great value on lineage. Therefore, military aristocrats will be defined as houses given to the profession of warfare, like the Sakanoue, Outomo, and the Mononobe. However, all of these families were before the institutionalization of the warrior households (and the allowance to carry weapons and practice violence) after the rebellions of Masakado and Sumitomo in the 10th century. These houses like the Kawachi Minamoto and the Ise Taira obeyed Imperial orders making them "servants of the court." They fought as mounted archers, and they were influential on the local scene as provincial governors and district magistrates. These 10th century "tsuwamono no ie" therefore play an important part in our definition. However, even as early as the 9th century, "houses that specialized in military affairs emerged" such as the Sakanoue.
The development of the aforementioned "on-site landlords" on Shouen (estates) around 1050 and after, improved the economy after difficult times of drought, famine, and epidemics. It also brought the peasant cultivators back onto the fields. These on-site landlords were like district magistrates, in that they dealt with the lowest levels of the populace who produced the agricultural products and were also "servants of the court." However, the district magistrates' profession was not guaranteed: they did not have the surety of their position like the military lineages of the late 10th century/early 11th century. Yet, the Minamoto fell out of favor after Yoshii's late 11th century Later Three Years' War. Therefore, surety of position shouldn't be counted as a prerequisite for being a samurai.
If we call samurai an "agrarian landlord," military aristocrats in the capital wouldn't be "samurai," even though they are the head of the warrior lineage, itself. Therefore, samurai are local notables (or from once-local lineages, like the Sakanoue) who served the court and were predominantly mounted archers. This definition obviously evolved in later periods of Japanese history. Strata of the samurai *did* have very strong ties to the land through jobs such as landlords, but that definition is too specific and discriminatory towards those members at court.
As mentioned, a "mounted archer" would allow the definition to go back to the 5th century. An "agrarian landlord" would allow the definition to apply to district magistrates and their unofficial successors, the on-site landlords under the shouen system, a span from the 8th to the 11th century, and exclude those at court. The multiple factors must therefore be present.
Therefore, when did the samurai emerge? I believe they emerged in the 11th century when "on-site landlords" (Farris' term), the shouen system, the Minamoto and Taira emerged, and the court greatly depended on these principally warrior houses for protection.