Hattori Hanzō, also known as Hattori Masanari, was a historical figure in Japan who lived during the Sengoku period (Warring States period) from the late 16th to the early 17th century. He was a renowned samurai and a trusted retainer of the powerful daimyo (feudal lord) Tokugawa Ieyasu.

Hattori Hanzō's birth and early life details are somewhat unclear, and there are different accounts and legends surrounding his origins. According to popular folklore and fictionalized portrayals, Hattori Hanzō was depicted as a master ninja and a skilled strategist. He is often associated with the Iga ninja clan and is said to have been the leader of the Hattori ninja, a group of highly trained covert operatives.

Hattori Hanzō's most notable historical role was serving as a trusted vassal of Tokugawa Ieyasu, who later became the shogun and established the Tokugawa shogunate, bringing about a long period of peace and stability in Japan. Hattori Hanzō played a crucial role in Ieyasu's rise to power and was known for his loyalty, intelligence, and military prowess.

His strategic abilities were demonstrated in various battles and campaigns, including the Battle of Mikatagahara in 1573, where he led a successful night raid against the Takeda clan forces. He also played a significant role in the Battle of Sekigahara in 1600, which resulted in Tokugawa Ieyasu's victory and the establishment of the Tokugawa shogunate.

Hattori Hanzō's fame and reputation grew over time, and he became a prominent figure in Japanese history and folklore. He is often portrayed as a legendary ninja and a symbol of loyalty, bravery, and martial skill. His name has been immortalized in various forms of media, including movies, television series, and video games, where he is depicted as a legendary warrior and ninja master.