The Samurai

History
The samurai first originated during the Heian period. The Japanese had launched several campaigns to subdue the native Emishi people in the Tohoku region. They employed individual warriors that were trained more extensively than regular soldiers to find and destroy the natives hiding spots. At the same time, many wealthy landowners that had become independent of the central government, hired these warriors to become part of the armys they had built for protection.
Eventually The two most powerful of these clans eventually challenged the central government, which resulted in a free for all battle between the government and the two clans for supremacy of the entire country. The clan led by Minamoto Yoritomo emerged victorious in 1192 and created a military government led by the Shogun (Supreme Military Commanders). These shogun samurai ruled over japan for close to 400 years after that.
In the 15th and 16th century however Japan had a major civil war and the entire country splintered into separate independent states. With each state battling for supremacy, The Samurai warriors were in high demand from each state, as they were the staple of japans military forces. This is the most recognizable period of time for the Samurai, with each separate clan engaged in constant battle, the samurai were always employed on military missions.
The country reunited around the 1500's and the samurai were placed in a high spot of the newly formed social cast system. Relative peace followed this and the need for warriors and feudal skills declined. Many samurai during this time became artists, teachers government officials. The order of Samurai eventually came to an end in the late 1800's.

Description of Samurai Armaments

The Samurai initially wore heavy armor know as "Yoroi". The Yoroi was made of individual scales of iron or thick leather Bound together to form strips. The strips were coated in a liquid that prevented water damage, and then fastened together with silk or leather strings to create chest armor. The need for heavier armor became necessary with the invention of firearms. The scales used in previous armors were replaced by broad plates over thick cloth. The helmets that the samurai wore were an important part of their uniform. Generally made out of iron, they were adorned with decorative and imposing features such as horns and masks made to look ferocious so to strike fear into their enemys. Their armor was often extremely unique and showcased an individuals rank and accomplishments. Frequently, these armors would be adorned with golden beams protruding from their helmets, or jewels on their shoulder and chest pieces.

The trademark weapon of the Samurai was of course the renown Samurai sword, which remains as the sharpest and sturdiest blade even today. The exact process used to make ancient samurai swords is not known but a similar technique is used today to make high quality sushi knives. The swords employed before the invention of the samurai sword were made of either iron or steel. the steel swords were able to have razor sharp edges, but the metal was prone to breaking as it was brittle. The iron swords were much more sturdy and were capable of bending, but could not hold as sharp an edge. A blacksmith basically decided he wasn't into that by creating a sword made of both iron and steel, fusing the two metals together to create a sword that was as sturdy as it was razor sharp. This was the samurai sword which made the warriors who equipped it some of the most feared in the ancient world. it was capable of slashing through most armors with ease as well as being swift, and not overbearingly heavy.

Other weapons employed by the samurai were composite longbows made from bamboo and leather, which were generally given to most warriors. Pole weapons such as spears and halberds were also used but not as widely utilized. The samurai were also know to use chains with either blades or iron balls on the ends, as well as, in later years firearms and cannons.

More info about Samurai.
http://www.japan-guide.com/e/e2127.html
http://www.encyclopedia.com/topic/samurai.aspx