* Image is for illustrative purposes only.Ishikawa Kazumasa
石川数正
Ieyasu's Right-Hand Man Who Defected to Toyotomi Hideyoshi
Description
Life
Ishikawa Kazumasa, born in Mikawa Province in the second year of Tenbun (1533), was a member of the Ishikawa family, which descended from the Seiwa Genji; his father was Ishikawa Yasumasa. Serving as personal attendant to the young Tokugawa Ieyasu, who lived as a hostage under Imagawa Yoshimoto, he thereafter distinguished himself in numerous battles as one of the two pillars of the Tokugawa house alongside Sakai Tadatsugu. He also worked to bring about the Kiyosu Alliance in the fifth year of Eiroku (1562), and he is known as a figure who supported Ieyasu's diplomacy toward Oda.
Heavy Responsibility as Castellan of Okazaki Castle
In the seventh year of Tenshō (1579), Kazumasa, who had served as guardian of Matsudaira Nobuyasu, Ieyasu's eldest son, took up the weighty post of castellan of Okazaki Castle after Nobuyasu's seppuku, the most painful incident in the history of the Tokugawa house. That he was entrusted with such a key position among the Tokugawa retainers shows how deeply Ieyasu trusted him.
The Decision to Defect
In the eleventh month of Tenshō 13 (1585), Kazumasa, who was then castellan of Okazaki Castle, suddenly left Ieyasu and defected to Toyotomi Hideyoshi, an act that shook the Tokugawa retainers. The reasons remain unclear to this day. Several theories coexist: that he became isolated within the Tokugawa house as an advocate of reconciliation with the Toyotomi house, or that Hideyoshi persuaded him to submit. The affair is still recounted as one of the great mysteries of Sengoku history.
Final Years as Lord of Matsumoto Domain
After leaving, Kazumasa was granted 80,000 koku in Kawachi Province by Hideyoshi. After the Odawara campaign in Tenshō 18 (1590), he was transferred to Matsumoto in Shinano Province with 100,000 koku (though some accounts say 80,000 koku), and he is regarded as the first lord of Matsumoto Domain. He devoted himself to building Matsumoto Castle as an early modern castle and to developing its castle town; his achievements survive today in Matsumoto Castle, a National Treasure. He died in the first year of Bunroku (1592) or in the following year, the second year of Bunroku.
Later Reputation
Although he was a close confidant of Tokugawa Ieyasu who turned to the enemy side, Kazumasa's life is repeatedly taken up in later historical novels and NHK Taiga dramas, as an anecdote embodying the tension between loyalty and self-preservation among Sengoku warlords.