Tokugawa Four Heavenly Kings: Ii Naomasa, the Red Devils, Trusted Confidant and Young Prodigy of Ieyasu

Forethought, Political Ability, and Broad Perspective; the Number One Trust from Ieyasu

The term “Four Heavenly Kings” originates from the guardian deities of Buddhism who reside in heaven: Jikokuten, Zoujouten, Koumokuten, and Tamonten, which have been worshipped in Japan. These deities gave rise to the term “Four Heavenly Kings,” especially used in the Warring States period to describe capable and powerful military commanders. A notable example is referring to Tokugawa Ieyasu’s most trusted retainers as the “Tokugawa Four Heavenly Kings.”

The “Tokugawa Four Heavenly Kings” refer to Sakai Tadatsugu, Honda Tadakatsu, Ii Naomasa, and Sakakibara Yasumasa. Among them, the youngest, Ii Naomasa, was exceptionally trusted by Ieyasu and was prominent in his rise to power.

Naomasa’s Ii clan had its stronghold in Iinoya, Tootoumi, prestigious since the late Heian period, but were treated dismissively by the Imagawa clan they served. Naomasa was born on February 9, 1561, as the legitimate son of Ii Naochika, who was killed by a retainer of Imagawa Ujizane when Naomasa was two. The Ii clan then was led by Naomasa’s aunt, Jirou-Houshi Naotora. Knowing Naomasa’s hardships, Ieyasu met the 15-year-old Naomasa in Hamamatsu and, acknowledging him as the son of a man who died for him, asked him to adopt the name Manchiyo in reference to his own childhood name, Takechiyo, and granted him 2000 koku of land in Iinoya, his ancestral land.

Naomasa’s first battle was at Shibahara against Takeda Katsuyori in February 1576. In this battle, Naomasa killed several spies of Takeda who had infiltrated Ieyasu’s sleeping quarters, earning him an additional 3000 koku for his bravery. He participated in many battles since, demonstrating his military prowess and political acumen. In 1580, he also performed meritoriously in the battle to recapture Takatenjin Castle, utilizing ninja to cut off the enemy’s water supply.

After the Honnō-ji Incident, during Ieyasu’s “Iga crossing”, Naomasa, as one of the Four Heavenly Kings, protected Ieyasu and served as an envoy for peace negotiations with the Hojo during the battles between Odawara-Hojo, Echigo-Uesugi, and the conflicts over Kai and Shinano Provinces (The Battle of Tensho Jingo). Subsequently, Ieyasu recognized Naomasa’s ability in both martial and political fields and used him flexibly in various roles.

After the collapse of the Takeda clan, Ieyasu absorbed many former Takeda retainers and ordered the organization of the “Ii’s Red Armored Guardian”, elite troops equipped in distinctive red armor, a legacy from the Takeda’s best warriors like Obu Toramasa and Yamagata Masakage. This was the origin of Ii’s Red Devils.

In 1584, Ieyasu, recognizing Naomasa’s foresight, political skills, and broad vision during the Komaki-Nagakute Campaign, entrusted him with 10,000 men out of the total 25,000 of the Tokugawa forces. After the Siege of Odawara, when Ieyasu moved to Kanto, he granted the 30-year-old Naomasa 120,000 koku in Ueno, Minowa, the highest among the Tokugawa retainers.

In September 1600, at the Battle of Sekigahara, Naomasa, acting as the guardian for Ieyasu’s fourth son, Matsudaira Tadayoshi, who was also his son-in-law, was shot twice while attempting to stop Shimazu Yoshihiro’s central breakthrough and was injured. After the battle, he was rewarded as “the most meritorious” and given the Sawayama Castle with 180,000 koku (later Hikone Castle). However, he passed away at the young age of 42, two years later, due to his gunshot wounds.

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