The Tokugawa Four Heavenly Kings: Why Sakai, Honda, Sakakibara, and Ii Were Named Together

The 'Tokugawa Four Heavenly Kings' refers to the four warriors — Sakai Tadatsugu (1527-1596), Honda Tadakatsu (1548-1610), Sakakibara Yasumasa (1548-1606), Ii Naomasa (1561-1602) — who bore the military core of Tokugawa Ieyasu's life.

It became widely known from the Edo through Meiji periods as the term for the representative hereditary retainers who supported Ieyasu's seizure of the realm.

But the term itself, in fact, is not one that took shape contemporaneously — it is a later evaluation that formed in the course of Edo-period house-tradition compilation.

The earliest use of the term 'Tokugawa Four Heavenly Kings' is sought in the military narratives and house-tradition materials of the middle to late Edo period.

In the primary sources from Ieyasu's lifetime and immediately after his death, no manner of speaking that bundles these four together appears.

The conception itself of paralleling the four to the Buddhist Four Heavenly Kings (the four deities guarding north, south, east, and west) has existed in Japan since medieval times, and in the Edo period a great many 'Four Heavenly Kings of such-and-such house' designations were generated in each daimyō house.

In the Tokugawa case as well, it is held to have settled more than a century after Ieyasu's death, in a context of honoring the four men.

Common features of the four men are clear. First, all were hereditary retainers from Mikawa.

Second, they served Ieyasu from his youth and took part in nearly all the major engagements of his life.

Third, after Sekigahara they were all elevated to fudai daimyō at 100,000 koku or more.

Fourth, each commanded an independent military group and functioned as one of the 'four pillars of the Tokugawa military body.

' These common features are corroborated in contemporary sources, and the Edo-period evaluation that bundles the four had empirical grounds.

The four were not homogeneous, and each bore a different role. Sakai Tadatsugu was the eldest, the chief elder retainer who had served from the time of Ieyasu's father Hirotada, taking charge of politics and diplomacy.

Honda Tadakatsu and Sakakibara Yasumasa were the core of actual-combat command, bearing breakthrough power on the field.

Ii Naomasa was the youngest, commanding Ieyasu's direct elite force 'Ii no Akazonae' (Ii's Red Devils) and functioning as a high-visibility charge unit.

The characters too are described in contrast: Sakai's maturity, Honda's bluntness, Sakakibara's craft, Ii's ferocity.

There were many other powerful warriors in the Tokugawa retainer body (Ishikawa Kazumasa, Ōkubo Tadayo, Hattori Hanzō, and others).

The reasons these four were chosen include, first, that they remained loyal to Ieyasu to the end (Ishikawa Kazumasa defected to Hideyoshi); second, that around Sekigahara they established their position as daimyō; and third, that their descendants survived through the Edo period as powerful fudai daimyō houses (the lines of all four continued until the end of the bakumatsu).

The Edo-period evaluation was based on contribution at the time of the establishment of the Tokugawa bakufu and on the survival of the family lineage afterward.

The 1600 battle of Sekigahara was a watershed for the Four Heavenly Kings as well.

Sakai Tadatsugu had already died; his son Ietsugu took the field. Honda Tadakatsu took part as a main eastern force, and after the battle was granted Ise Kuwana at 100,000 koku.

Sakakibara Yasumasa did not take the field but garrisoned Edo, and after the battle was granted Kōzuke Tatebayashi at 100,000 koku.

Ii Naomasa was the eastern vanguard, died in 1602 from wounds taken in the battle, and after the battle was granted Ōmi Sawayama at 180,000 koku.

All four houses established their position as Tokugawa-bakufu fudai daimyō houses and held senior posts through the Edo period.

In contemporary scholarship, the standard understanding is two-sided: the term Tokugawa Four Heavenly Kings is taken as a product of Edo-period house-tradition compilation, while the substance — that the four bore the military core of Ieyasu's body — is itself recognized as historical fact.

Irimoto Masuo's The Tokugawa Four Heavenly Kings (Shin-Jinbutsuōraisha) and other empirical studies that treat the four together continue.

The cultural tradition of honoring the four military cores of the founding process of a warrior government as 'Four Heavenly Kings' formed within the 260-year stability of the Tokugawa bakufu — and is itself studied as a phenomenon reflecting the historical consciousness of Edo-period society.