was a samurai

Samurai

is the term for the military nobility of pre-industrial Japan. According to translator William Scott Wilson: "In Chinese, the character 侍 was originally a verb meaning to wait upon or accompany a person in the upper ranks of society, and this is also true of the original term in Japanese, saburau...

 of the Sengoku period

Sengoku period

The or Warring States period in Japanese history was a time of social upheaval, political intrigue, and nearly constant military conflict that lasted roughly from the middle of the 15th century to the beginning of the 17th century. The name "Sengoku" was adopted by Japanese historians in reference...

, in the 16th century of the common era

Common Era

Common Era ,abbreviated as CE, is an alternative designation for the calendar era originally introduced by Dionysius Exiguus in the 6th century, traditionally identified with Anno Domini .Dates before the year 1 CE are indicated by the usage of BCE, short for Before the Common Era Common Era...

, who served as an important retainer

Retainer

Retainer may refer to:* Retainer , a person, especially a soldier, in the service of a lord in the late Middle Ages** Retainer sacrifice, the sacrifice of a human servant* Retainer...

 of the Sanada clan

Sanada clan

The was a Japanese clan which rose to prominence in the Sengoku period. During the Edo era, the Sanada ruled the Matsushiro Domain, where they remained until the Meiji Restoration.-Sengoku period:...

.

Genba was allegedly born in Sawatari, Shinano province

Shinano Province

or is an old province of Japan that is now present day Nagano Prefecture.Shinano bordered on Echigo, Etchū, Hida, Kai, Kōzuke, Mikawa, Mino, Musashi, Suruga, and Tōtōmi Provinces...

, and was originally an officer of Iwabitsu Castle

Iwabitsu Castle

is a "yamashiro" located on Mount Iwabitsu in Higashiagatsuma, Gunma Prefecture, Japan.-History:Iwabitsu Castle was built in the fifteenth century by Azuma Taro Sukefusa of the Takeda clan. It later came under control of the Saitō clan . The castle once again came under control of the Takeda Clan...

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Sanada Masayuki

Sanada Masayuki

was a Japanese Sengoku period daimyo. He was the third son of Sanada Yukitaka, a vassal daimyo to the Takeda family in Shinano province. He is known as a master strategist. Sanada Nobuyuki and Sanada Yukimura were his sons.-Biography:...

 and Sanada Yukitaka

Sanada Yukitaka

was a daimyō of Shinano Province who became one of Takeda Shingen's 'Twenty-four Generals' , submitting to become Takeda's vassal after a long and difficult struggle against him....

 were very good at persuading their opponents to defect. Their great talent in this field led them to win victories over many castles when infiltrated. Genba was one of those former enemies persuaded to defect, and thereafter went on to serve under the Sanada.

As a Sanada retainer, Genba sneaked into Shiritaka Castle with his colleagues and burned it. He participated in the Battle of Nagashino

Battle of Nagashino

The ' took place in 1575 near Nagashino Castle on the plain of Shitaragahara in the Mikawa province of Japan. Forces under Takeda Katsuyori had besieged the castle since the 17th of June; Okudaira Sadamasa , a Tokugawa vassal, commanded the defending force...

 in 1575. When Takeda

Takeda Katsuyori

was a Japanese daimyo of the Sengoku Period, who was famed as the head of the Takeda clan and the successor to the legendary warlord Takeda Shingen. He was the son of Shingen by the , the daughter of Suwa Yorishige...

, the lord of Sanada, lost that battle, Genba escaped and returned to his land.
In popular culture, Genba is frequently depicted as a Ninja

Ninja

A or was a covert agent or mercenary of feudal Japan specializing in unorthodox arts of war. The functions of the ninja included espionage, sabotage, infiltration, and assassination, as well as open combat in certain situations...

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