The Ii were a clan who originated in Tōtōmi, and had held the lands in and around Iinoya for generations, with their roots being of the indigenous population rather than any particular noble bloodline.
Supposedly, their founder, Ii Tomoyasu, had been an exceptionally gifted commoner of mysterious origins who was adopted into the Fujiwara clan, and settled at the place of his ‘birth’ [discovery] - Iinoya.
Although small, the clan would eventually expand its influence significantly in the last decades of the Sengoku period, under the rule of Jirō Hōshi and her successor, Ii Naomasa.
Ii Naomasa was born the first son of Ii Naochika in the spring of Eiroku 4 (1561), and he was given the childhood name of Toramatsu. At that point, the Ii were in a tense position, as their previous head, Naomori, had died at Okehazama the year previously.
A year after his birth, Naomasa’s father was said to have been planning to ally with the Tokugawa, who had rebelled against the Imagawa after Okehazama. For this act, Naochika had to go to Sunpu and explain his actions, but he never reached his destination - he was instead assassinated en-route, alongside his retainers, by Asahina Yasutomo.
This was all said to have been orchestrated by the Ii’s chief retainer, Ono Masatsugu, in order to allow him to take control of the Ii while it was at its most vulnerable.
However, his plans were foiled by the head monk of Ryōtan-ji, Nankei Zuimon and Jirō Hōshi, the daughter of Naomori who several years prior had become a monk at the temple, who became the regent of the Ii instead.
This did not necessarily guarantee the survival of Toramatsu, however, as he was the son of a traitor. Niino Chikanori, a relative of the Ii, pleaded the case for Toramatsu’s survival, as he was so young, and as a result he was allowed to live.
Toramatsu was raised by his mother, Hiyo, his cousin Jirō Hōshi, and Jirō’s mother, the cloistered Yūchin-in.
In Eiroku 11 (1568), the Takeda of Kai invaded Sunpu, and knowing the flimsy loyalties of the Ii, Ono Masatsugu was supposedly ordered by Imagawa Ujizane to take over Iinoya and kill Toramatsu.
The Ii sought refuge in Ryōtan-ji in order to escape such a fate, and all seemed hopeless for a brief period of time.
Tokugawa Ieyasu, hearing of the Ii’s plight, sent the Iinoya San-Nin-Shū (Iinoya Three) to recapture Iinoya for the Ii. Although Masatsugu managed to escape, he was eventually captured and executed by Ieyasu.
These actions brought the Ii over to the Tokugawa’s side, thus causing the exact thing that the Imagawa had hoped to avoid.
In Tenshō 2 (1574), at age thirteen, Toramatsu’s mother Hiyo remarried to Matsushita Kiyokage, a Tokugawa vassal, and Toramatsu was for a time adopted into the Matsushita clan.
There, he again met with Ieyasu, who decided to take him in as his page, allowing him to rejoin the Ii clan and giving him a new name of Manchiyo.
Jirō Hōshi continued to act as his regent during this time, ruling Iinoya in his stead while he served Ieyasu for the next few years.
In Tenshō 9 (1581), Manchiyo participated in his first notable battle, aiding in the retaking of Takatenjin Castle, which had been lost seven years prior to the Takeda.
In Tenshō 10 (1582), Jirō Hōshi passed away, with Manchiyo succeeding her as ruler of Iinoya - taking on the name Naomasa.
Later that year, the Honnō-ji Incident took place, resulting in the death of Oda Nobunaga. Naomasa was among those who accompanied Ieyasu from Iga back to Mikawa, after having convinced him not to commit suicide to follow Nobunaga in death.
He also aided in the Tokugawa annexation of Shinano and Kai, the former territories of the Takeda. It was here when several of Takeda’s former vassals came under his service and he became a general. Ieyasu ordered Naomasa to take over the Takeda military strategy of painting their armour a crimson red, which had begun under the command of Yamagata Masakage. Thus - the Akazonae of the Ii were formed.
In Tenshō 12 (1584), Naomasa had the opportunity to lead the Akazonae in their first battle, at Komaki and Nagakute, against the forces of Hideyoshi Hashiba (the future Toyotomi Hideyoshi).
This was when he earned his nickname ‘Akaoni-no-Ii’, not only because of the distinct horns on his helmet which resembled that of an oni, but also because of his fierce behaviour in the battlefield.
Although the Tokugawa would eventually submit to Hideyoshi in Tenshō 14 (1586), Naomasa’s skill was taken note of, as he was made the highest-ranking warrior of the Tokugawa.
During the Siege of Odawara in Tenshō 18 (1590), Naomasa was the commander who was the first to breach the walls of the castle, attacking during the night while no one expected it and leading the charge, which made him known across the country.
In Keichō 3 (1598), while Naomasa was with Ieyasu in Kyoto, Hideyoshi passed away, and the battle to see who would inherit his will was about to begin.
In the ensuing power struggle, Naomasa would act as a negotiator for the pro-Tokugawa faction, swaying several warlords over to Ieyasu’s side.
This would continue for the next two years, until the Battle of Sekigahara in Keichō 5 (1600).
It is said that the battle started when Naomasa and Matsudaira Tadayoshi led a sneak attack, even though it had been decided earlier that Fukushima Masanori was the one who was supposed to take the lead.
At the climax of the battle, Naomasa took out Shimazu Toyohisa, and while in pursuit of his uncle Yoshihiro, was shot in the leg and fell off his horse, causing a serious injury which would eventually lead to his demise.
Despite his injury, Naomasa made the efforts to negotiate with the Mōri, Shimazu, and Sanada clans, amongst others who had been a part of the Western Army, allowing them to serve the Tokugawa in the future.
After the war was over, Naomasa was granted the former territory of Ishida Mitsunari, the face of the Western Army.
Naomasa allowed many of the policies that Mitsunari had started to carry over into his rule, and allowed its citizens, who greatly respected their former lord, to openly grieve for his passing.
Yet, it would not last for long.
On the first day of the second month of Keichō 7 (1st February, 1602), Ii Naomasa died at Sawayama Castle at the age of forty-one. Supposedly, the injury he had received at Sekigahara had worsened, and he had contracted tetanus, which led to his death.
It is said that when he passed away, his men did not commit ritual suicide in order to follow him to the grave, as was tradition, due to Naomasa’s last command to them all to ‘live’.