Matsudaira Kiyomasa (1561-1641) was a prominent Japanese samurai and feudal lord during the late Sengoku period. He served the Tokugawa shogunate and played a significant role in the unification of Japan. Kiyomasa was known for his military prowess and loyalty, particularly during the Battle of Sekigahara in 1600, which solidified the Tokugawa's power. Kiyomasa governed the Kumamoto Domain in present-day Kumamoto Prefecture. He is also remembered for his contributions to infrastructure, including the construction of Kumamoto Castle, which remains a historical landmark. His legacy includes a reputation for both military skill and effective governance.