Our story begins in the ninth century, on a small collection of island nations that would become known as Japan. It was not Japan as we think of it today, as at this time the island was dotted with countless, independent kingdoms that were connected through complicated political and economic relationships akin to the feudalism of the early Middle Ages in Europe. The ruling class were the land owning lords, known as Daimyos.
Daimyoswere faced with a constant threat of warfare, and to defend themselves they hired mercenary warriors to man and lead their armies.
Most of the warriors during this period were horsed archers - the bow was the pinnacle of military technology and archery was considered the most important skill for a warrior to have. These hired warriors were given privileged status by their local Daimyo in exchange for their service and over time, this lead to the establishment of these warriors as a noble class. These fighting nobles became known as Samurai.
As smaller kingdoms were absorbed by larger neighbors, warfare was held on a larger and larger scale. The importance of raiding forces like horsed archers was reduced and infantry became more important. Samurai began to fight with sword and spear as well as the bow. Some time after 900 A.D. all Samurai began to carry swords and were primarily sword fighters.
By the 1100s Samurai were a full warrior culture, and had become the ruling class of Japan; all Daimyo's were Samurai. As a noble class, Samurai were part of a very small percentage of people that did not rely on growing their own food to survive. They lived off food grown by others, giving them free time to perfect their craft: warfare.
Samurai that survived to old age would teach their successful skills to others at fighting academies, to which Samurai would send their sons to learn the ways of war. Over the next few centuries, these academies sprang up all over the dozens and dozens of nations that covered Japan. One of the skills a young Samurai would learn at these academies was the close combat are of Jujitsu.
Jujitsu developed as an unarmed martial art in a culture where basically everyone was armed, so the first goal was to deal with an attacker's weapon. Samurai would train to defend against swords, spears or knives. While strikes targeting the eyes, nose, groin and other vital points were incorporated, striking was not the focus of Jujitsu because Samurai armor would negate their effectiveness.
The nations of Japan had relative peace under the rule of military dictators known as Shogun and each nation had its own army of highly trained Samurai. But as the power of the Shogun slowly weakened, tensions between rival nations grew.
In the mid 1400's the powder keg that was Japan finally exploded into all-out war and for the next 200 years Japan would be embroiled in almost constant warfare. The Samurai were on the front lines for all 200 years of these wars and during this time Jujitsu experienced a trial by fire.
In battle, Samurai would take down armored enemies, when opportunity presented, with an array of trips and throws. Normally these would be used after a clash of swords to gain a lethal advantage. Once the dominant position was attained, the victorous Samurai would quick dispatch his vicitim with anything from his sword, to eye gouges, to the fallen man's own knife.
Here is an example of traditional Jujitsu, from the Takenouchi style: