Ishida Mitsunari (1560-1600) was discovered by Toyotomi Hideyoshi as a boy, famously serving tea in three cups at progressively hotter temperatures to show thoughtfulness. He rose to become Hideyoshi’s chief administrator, excelling in logistics and finance. After Hideyoshi’s death in 1598, Mitsunari opposed Tokugawa Ieyasu’s growing power and organized the Western Army at the Battle of Sekigahara (15 September 1600). Despite initial balance of power, the defection of Kobayakawa Hideaki caused total Western Army collapse. Mitsunari was captured and beheaded on 1 October 1600, at age 40. His famous last anecdote — refusing a persimmon before execution saying ‘it is bad for phlegm’ — illustrates his composed dignity. Key sites: Sekigahara Battlefield (Gifu), Nagahama Castle (Shiga), and Azuchi Castle Ruins (Shiga).