Historically, Japanese samurai were warriors that followed a strict code and were diligent in their martial art training and their devotion to the art of the samurai sword. The samurai were the highest of four main classes in Japan, with the others being farmers, artisans, and merchants. In feudal Japan, a samurai was employed by a lord and alotted a wage, measured in rice, depending on the merit of the samurai. The origins of samurai are thought to go back to the Heian period (794-1192).
The samurai are often known for their moral code, called bushido, that stressed the importance of loyalty to the samurai's lord, even to the point of offering up one's life to do the right thing. One of the more well known accounts of bushido are contained in the book Hagakure.
Samurai trained with many weapons, but the sword held a special place in their practicing, fighting, and way of life. Training with wooden swords, an art known as kendo that is still practiced today, samurai honed their skills as well as learned the principles of strategy. Samurai were the onle ones who could carry swords, and they usually carried two, a long one, known as a katana, and a short companion sword, called a tanto.
In addition to just being warriors, samurai were known for their appreciation for writing and the fine arts. The ability with the brush was admired along with the skills with the sword. It was common to write poems, especially for certain occasions. The writings and paintings of Musashi Miyamoto are considered to be among the most famous works of that period.
In Tenchu Samruai are the oppisite of a ninja in the sense that that lack the same general skills that a ninja has. Samurai are often ambushed by the protagonist if the player chooses to be strategic in play-style, or they are massacred in single combat by the player, evidently this is far less effective in Tenchu games than using stealth to claim them one by one. Rikimaru and Ayame (generally the protagonists of all the Tenchu games aside from Tenchu Z) often face levels with a majority of their opponents being unarmored and unprepared "guards" wielding either a Katana, spear or bow however in later levels they are less and less common being replaced with enemy Ninja and demons...Samurai are not trained as such that they can match the speed and graceful swiftness that a Ninja will often possess but occasionally they will use Shuriken and Caltrops oddly effectively .During war between Goda and Ogawara it became apparent that Ogawaran Samurai were far more numerous and far better trained as Goda almost always couldn't succeed in skirmishes and major battles without help from its native assassin clan: The Azuma Ninja. To that end it can be safely assumed that without its trump card Ghoda would have certainly been obliterated. On a side note not all the Samurai in the game are against you, this is uncommon however. It is unknown why in the events Tenchu Z it is stated that masterless samurai buy blunt swords from shady merchants or trade with pirates. It could be that they are unaware of the intent of their trade partners until it is to late. Unlike the player when Samurai fall in water they will die as with all enemies including enemy ninja they cannot swim and drown (This is a good way of defeating difficult opponents) . Samurai have also been leveled with the difficulty in terms of locating the player, as in the harder the difficulty the better the Samurais senses will be (in Tenchu Z anyway) it is important to note that all enemies will be subject to the same leveling. Samurai will never surrender and will die before they allow an assassin to murder their master or payee. Guards are placed in levels to ensure that the mos direct routes to the targeted person, item or objective is difficult to reach. In Tenchu Z at you progress through levels you will come across missions that have the same map with the guards placed very differently in order to add difficulty. Some guards like the Tomikichi are somewhat hidden in all the levels in the game and as a result careless or unwary players may accidentally stumble across them and be detected. As the game is set in Feudal Japan (16th Century) the majority of opponents as stated before will be Samurai who are unarmoured and not battle ready.
Katana: A curved longsword used by Samurai and Samurai masters as a slashing weapon. Unlike the Ninjato it has a considerably larger damage output and striking range it however is trumped and outclassed by the Ninjatos speed and mobility. The blade is sheathed on the hip tied into the Kimono in an "upside down" fashion.
Spear: A long pole like weapon with a straight blade at the end of it. The spear is a common weapon in Feudal Japan as was historically used as a response to Calvery and troop charges. In Tenchu the spear can either be used in a thrusting or slashing fashion. Like the Katana it's damage output is impressive and it has a very large striking distance, it is somewhat faster to. However Samurai/Gaurds using it are subject to lower mobility and can easily be out maneuvered.
Longbow: The Samurai use a Japanese take on the common longbow, historically the Longbow was used by Calvery and archer battalions against grouped opponents and armored targets it was eventually made obsolete by the introduction of gunpowder and flintlock rifles. In the game the bow has a medium damage output and can knock you off your feet at closer range. It is slow and lacks mobility, but is balanced by its users good vision and accuracy. Archers however are very outclassed in close quarters and while being targeted by several opponents.