Ii Naomasa was born in Hōda Village of
Tōtōmi Province. His childhood name was Toramatsu (虎松), later Manchiyo (万千代). His family, like the Tokugawa, had originally been retainers of the
Imagawa clan, but following the death of the clan's leader,
Imagawa Yoshimoto, in the
Battle of Okehazama (1560), confusion and general chaos ensued. Naomasa's father,
Ii Naochika, was falsely convicted of treason by Yoshimoto's paranoid successor,
Imagawa Ujizane, and was subsequently killed.treason. Naomasa, then a very small child, escaped his danger. After many difficulties,
Ii Naotora succeeded the
Ii clan and become the guardian of Naomasa. It was said the house of Ii clan invested greatly in Naomasa's education in preparation to entrust him to Ieyasu as a bid to save the Ii clan from crisis. which joined the Tokugawa clan's rank after Ieyasu's invasion of Totomi in 1568. As they entered service under Ieyasu, they were placed by Ieyasu under The command of Naomasa.
War against Takeda & Hōjō clan In 1576, Naomasa fought for the first time in the battle against Takeda Katsuyori's forces at Shibahara (芝原) in
Tōtōmi Province. Later Naomasa was seen alongside Ieyasu's
Hatamoto vanguards, alongside Honda Tadakatsu and Sakakibara Yasumasa. At the age of 18, Naomasa participated in the Tokugawa army attack on Tanaka castle which guarded by Takeda clan general named
Ichijō Nobutatsu. In this battle, Naomasa fought together with Matsudaira Ietada, Sakakibara Yasumasa, and Honda Tadakatsu as they all climbed to Tanaka castle wall and fighting Nobutatsu's soldiers. In 1578, at the age of 18, Naomasa was given control of 10,000 koku of domain, due to unspecified distinguished military merit during that year. It was said that during this period, Naomasa gained Ieyasu's favor due to his blood relation with
Lady Tsukiyama, Ieyasu's legal wife. As they reached Kada, an area between
Kameyama town and Iga, the attacks from Ochimusha-gari finally ended as they reached the territory of
Kōka ikki Jizamurai warriors who were friendly to the Tokugawa clan. The Koka ikki warriors then escorted the group while assisting them by eliminating the threats of the Ochimusha-gari outlaws until they reached
Iga Province, where they were further protected by samurai clans from
Iga ikki which then accompanied the Ieyasu group until they safely reached Mikawa. After Ieyasu's return to Mikawa,
Tenshō-Jingo War broke out between the Tokugawa clan and
Hōjō clan in a contest to gain control the area of
Shinano Province,
Ueno region, and
Kai Province Kai Province (currently Gunma Prefecture), which had been vacant since the destruction of
Takeda clan and the death of Oda Nobunaga. Ieyasu lead an army of 8,000 soldiers entering Kai,
Shinano Province, and Ueno, to annex it. However, the
Hōjō clan in the
Kantō region also led an army of 55,000 men and crossed the Usui Pass to invade Shinano Province. In the battle of Wakamiko, 8,000 Tokugawa soldiers fought against around 50,000 soldiers of Hojo soldiers led by
Hōjō Ujinao. Ii Naomasa was recorded as participating in these engagements. In the middle of this conflict, Naomasa further managed to recruit more samurais that had formerly served various Takeda generals such as
Ichijō Nobutatsu,
Yamagata Masakage, Masatsune Tsuchiya, and
Hara Masatane with the help of former Takeda clan retainer named Kimata Morikatsu who organized the contacts of those samurais with Naomasa. Aside from military service, Naomasa played diplomatic role during this conflict as he received around 41 letters from many former Takeda clan's vassals to submit to Ieyasu. In total, more than 800 vassals of Takeda clan from Kofu Province recruited by Ieyasu during the fight against the Hōjō which lasted for 80 days. In the final phase of this conflict, Naomasa participated in the battle of Kurokoma, where the smaller Tokugawa army managed to defeat the much larger Hōjō armies, despite being reinforced by 10,000 soldiers by
Satomi clan from
Awa Province (Chiba). From November to January of the following year, Naomasa worked together with another Tokugawa general Torii Mototada, and two former Takeda clan generals who now joined Tokugawa clan's rank,
Hoshina Masanao and Suwa Yoritada, to attack
Chikuma District which was controlled by a Hōjō clan vassal named Ogasawara Sadayoshi. By February 10, Sadayoshi surrendered and joined the Tokugawa side. The result of this war, combined with the defection of
Sanada Masayuki to the Tokugawa side has forced the Hōjō clan to negotiate truce with Ieyasu. The Hōjō clan then sent Hōjō Ujinobu as its representative, while the Tokugawa sent Naomasa as its representative to negotiate the peace conditions. According to the
Meishō genkō-roku record, after the conflict with the Hōjō clan, Ieyasu
organized a kishōmon(blood oath) with many samurai clans that formerly were vassals of the Takeda clan assigned under the command of Tokugawa clan retainers. Ieyasu Tokugawa planned to subduct the largest portions of former Takeda samurai under Naomasa's command, having consulted and reached agreement with Sakai Tadatsugu, a senior Tokugawa clan vassal. However, Ieyasu's decision garnered protest from Sakakibara Yasumasa, who went so far as to threaten Naomasa. Tadatsugu immediately defended the decision of Ieyasu in response and warned Yasumasa that if he did any harm to Naomasa, Tadatsugu would personally slaughter the
Sakakibara clan; thus, Yasumasa heeded Tadatsugu and did not protest further. Then Ieyasu decided assigned 70 members of former Takeda samurais from
Tsuchiya clan under the command of Ii Naomasa. During this year, Naomasa was also given an increase of his domain to 40,000 koku. Later in 1583, Naomasa sent a detachment of former Takeda samurai who originated from Kai, and were led by his subordinate, Kimata Morikatsu, to invade the Takatō area of
Shinano province and subdue an area there which had still not submitted to the Tokugawa clan. In this battle, Naomasa fought so valiantly that it elicited praise from
Toyotomi Hideyoshi, who was on the opposing side. After the Battle of Komaki and Nagakute, the front line in northern Owari reached a stalemate. Ieyasu and
Oda Nobukatsu led 20,000 soldiers and besieged three castles: Kanie Castle, Maeda Castle, and Shimoichiba Castle. The Kanie castle was defended by
Maeda Nagatane and
Takigawa Kazumasu. Tadatsugu, Okanabe Mori, and Yamaguchi Shigemasa spearheaded the attack towards Shimoichiba castle. On June 22, Nobukatsu and Ieyasu launched an all-out attack on Kanie Castle. The soldiers were led by Tadatsugu, While Naomasa, Ishikawa Kazumasa, Honda Tadakatsu, Sakakibara Yasumasa, and Matsudaira Ietada were deployed in reserve before entering the battle with Ieyasu himself. On June 23, Ieyasu entered the castle with Sakakibara Yasumasa, thus the castle was subdued. In 1585, during the Tokugawa clan's first siege of
Ueda Castle against
Sanada Masayuki, Ii Naomasa led 5,000 soldiers along with Osuga Yasutaka and
Matsudaira Yasushige led reinforcements to cover the retreat of Tokugawa forces after they failed to pacify the castle due to hostile movements from
Uesugi Kagekatsu. In the same year,
Ishikawa Kazumasa, a senior vassal of Tokugawa, defected from Ieyasu to Hideyoshi. This incident caused Ieyasu to undertake a massive reform of the structures of the Tokugawa clan's military government. At first, Ieyasu ordered Torii Mototada, who served as the county magistrate of Kai, to collect military laws, weapons, and military equipment from the time of Takeda Shingen and bring them to Hamamatsu Castle (Hamamatsu City, Shizuoka Prefecture). Later, he also appointed two former Takeda vassals, Naruse Masakazu and Okabe Masatsuna, as magistrates under authority of Ii Naomasa and Honda Tadakatsu, while he also ordered all of former Takeda vassals who now serve him to impart any military doctrines and structures they knew during their service under Takeda clan, and lastly, he ordered the three of his prime generals, the so-called "
Tokugawa Four Heavenly Kings," Ii Naomasa, Honda Tadakatsu, and Sakakibara Yasumasa, to serve as supreme commander of this new military regiments. In 1586, according to "
Sakakibara clan historical records", Ieyasu sent Naomasa, Honda Tadakatsu, and Sakakibara Yasumasa as representatives to
Kyoto, where the three of them were regarded as "
Tokugawa Sanketsu"(Three great nobles of Tokugawa). Then in following month, the three of them were joined by Sakai Tadatsugu to accompany Ieyasu in his personal trip to Kyoto, where the four of them "became famous". In 1587, during the campaign of Toyotomi Hideyoshi against the
Ikkō-ikki rebel armies, the Tokugawa clan were involved in the battle of Tanaka castle in
Fujieda, Shizuoka. In 1588, during a visit of the Tokugawa clan to pay respect to Toyotomi Hideyoshi, Naomasa was appointed to the rank of Jijū (equivalent of English
Chamberlain office), and became the highest-ranking senior vassal in the Tokugawa family. This made Naomasa outrank even the most senior of Tokugawa's officers such as Sakai Tadatsugu. in 1590 May, Naomasa participated with the Toyotomi forces during the
campaign against the Hōjō clan. Later, when
Minowa Castle surrendered without a fight, it was awarded to Ii Naomasa as its castellan. Naomasa significantly expanded the castle and dug deep and wide dry moats and replaced earthen ramparts with stone walls along the main route into the castle. The siege of Odawara, as the last Hōjō clan stronghold, nearly saw no significant military action, with the exception of Naomasa's night raid attack. This happened after a group of miners from
Kai Province dug under the castle walls, allowing men under Ii Naomasa's command to enter and engage the enemy. It was recorded by
Miura Joshin, a Hojo samurai and poet who also participated in this conflict; that Naomasa's unit managed to kill 400 Hojo soldiers. After the surrender of the Hōjō clan, Ieyasu sent Naomasa and Sakakibara Yasumasa with 1,500 soldiers to witness the
Seppuku suicide ritual procession of the defeated enemy generals,
Hōjō Ujimasa and
Hōjō Ujiteru. As result of his meritorious service during this campaign, Naomasa was awarded with an increase of domain stipends to 120,000 Koku.
Rebels suppression campaign (1590-1591) Later in October 28 of the same year, a
massive rebellion against the Toyotomi government in
Mutsu Province which was incited by Hienuki Hirotada and Waga Yoshitada broke out. In response, Hideyoshi sent a punitive expedition with 30,000 army in strength led by Ieyasu Tokugawa,
Toyotomi Hidetsugu,
Date Masamune,
Ishida Mitsunari,
Ōtani Yoshitsugu,
Gamō Ujisato,
Uesugi Kagekatsu,
Satake Yoshishige, and
Maeda Toshiie, in order to pacify those rebellions. Naomasa who participated in this expedition brought in his "Red Demons" unit as vanguard of Tokugawa forces. Subsequently, with the Waga-Hienuki rebellion, the
Kunohe rebellion also broke out in March 13, 1591. This caused the punitive expedition army to take the measure of splitting their forces as Ieyasu, Naomasa, Ujisato, and some commanders now changed their focus to suppress Masazane's rebellion first. Naomasa also brought some veteran vassals such as Kondō Hideyo here. As the operation commenced, Naomasa became part of the army who besieged Kunohe castle, where he and Asano Nagamasa deployed on the east side across the Nekobuchi River. On 4 September, the rebels executed the prisoners inside the castle and committed mass suicide after setting a fire which burned the castle for three days and three nights and killed all within. while Hienuki Hirotada was sentenced to "
Kaieki law" which stated that he and his clan's status and rights as samurai were stripped.
Sekigahara campaign & its aftermath In 1598 after Hideyoshi died, political strife occurred between Ieyasu and the other Toyotomi clan's regents. Naomasa undertook political initiatives as he built a relationship with
Kuroda Yoshitaka and
Kuroda Nagamasa and formed a pact. through the Kuroda clan, Naomasa successfully swayed the other military commanders to support the Tokugawa clan. Aside from the Kuroda clan, according to a letter of Naomasa which is preserved in modern-day Hikone Castle Museum, Naomasa also engaged in correspondence with
Sanada Nobuyuki to gain his support for the Tokugawa clan in response to a predicted incoming conflict between Ieyasu and his political enemies. In the same year, Naomasa also built
Takasaki Castle and relocated his seat there. Minowa Castle was abandoned and allowed to fall into ruin. In 1600, on the eve of the
Sekigahara campaign, Naomasa led the forces in the Tokaido area together with Honda Tadakatsu, and played a central role as Ieyasu's representative. On August 21, The Eastern army's alliance, which sided with Ieyasu Tokugawa, attacked Takegahana castle which was defended by
Oda Hidenobu, who had sided with Mitsunari's faction. They split themselves into two groups, where 18,000 soldiers led by
Ikeda Terumasa and
Asano Yoshinaga went to the river crossing, while 16,000 soldiers led by Naomasa,
Fukushima Masanori,
Hosokawa Tadaoki, Kyogoku Kochi, Kuroda Nagamasa,
Katō Yoshiaki,
Tōdō Takatora, Tanaka Yoshimasa, and Honda Tadakatsu went downstream to
Ichinomiya. The first group led by Terumasa crossed the Kiso River and engaged in a battle at Yoneno, causing the Hidenobu army to be routed. On the other hand, Takegahana castle was reinforced by a Western army faction's general named Sugiura Shigekatsu. The Eastern army led by Naomasa and Fukushima crossed the river and directly attacked Takegahana Castle at 9:00 AM on the August 22nd. Shigekatsu himself set the castle on fire and committed suicide as a final act of defiance. and Ii Naomasa's Positions in the Sekigahara battle. On October 21, in the
Battle of Sekigahara, Naomasa gave a notable performance where his unit outpaced those of other generals such as
Fukushima Masanori, drawing the "first blood", where Naomasa led 30 spearmen from the center of the formation and charged the ranks of the western army, and then he was followed by Masanori whose units started clashing against
Ukita Hideie units. However, some modern historians now view Naomasa's actions as a result of confusion on both sides as there was heavy fog covering the battlefield, and this may have caused him to unintentionally start the first clash against the enemy, which broke Ieyasu's previous order to let Masanori perform the first move of the battle. Meanwhile, Professor Watanabe Daimon offered an explanation that by many indications according to the battle records, the assignment of Naomasa as
Ichiban-yari or the first unit to charge the enemy were already settled before the battle, where Masanori had agreed with Naomasa's intention to lead the first attack. Daimon argued that as Naomasa was appointed by Ieyasu supreme field commander, Naomasa was responsible for all commands and strategies during the clash in Sekigahara. As the battle entered its final phase, Naomasa turned his attention towards the Shimazu troops. After the Sekigahara battle, Naomasa sought pardons with Ieyasu for
Sanada Masayuki and
Sanada Yukimura at the behest of
Sanada Nobuyuki. Naomasa also had his fief increased from 60,000 koku into 180,000 koku. Naomasa complained of this to Nagai Naokatsu, as he considered it small when compared to
Ikeda Terumasa who received 520,000 Koku. After defeating the Western Army at Sekigahara, Ieyasu dispatched his army to attack
Sawayama Castle in
Ōmi Province, the former territory of
Ishida Mitsunari with
Kobayakawa Hideaki's troops at the vanguard. Most of the castle's troops were at the Battle of Sekigahara, leaving the castle's garrison at 2,800 men. Despite the absence of the lord of the castle, the castle's soldiers fought well, but eventually some soldiers such as Moritmo Hasegawa betrayed the castle and opened the castle for the besieging army. most of Mitsunari relatives, including his father Masatsugu, Masazumi, and Kagetsuin (Mitsunari's wife), were killed in battle or committed suicide. After the castle fell in 1601, Naomasa was appointed to take control of Sawayama Castle, However, as the castle was viewed as unstrategic in location, Naomasa ordered the castle building along with its structures dismantled, while transferring its materials instead to Kohei castle, another castle which was controlled by Naomasa. He also was appointed to the rank of Junior Fourth Rank. Several months after the battle in Sekigahara, Naomasa sent military reinforcements to assist
Yamauchi Kazutoyo in pacifying the rebellion in
Tosa Domain against retainers of
Chōsokabe clan, and the
Ichiryo Gusoku peasant army. The wound which was suffered by Naomasa at Sekigahara prevented his personal involvement in the quelling of the last vestiges of the anti-Tokugawa faction. The 273 dead rebels heads were decapitated and sent to Ii Naomasa.
Death Ii Naomasa's premature death in 1602 has been widely blamed on the wound he received at
Sekigahara. Naomasa was highly regarded by
Tokugawa Ieyasu, so it is no surprise that his sons
Naotsugu and
Naotaka succeeded him in his service and title. However, Naotsugu managed to anger Ieyasu by refusing to take part in his campaign to reduce the
Toyotomi clan stronghold at
Osaka. In 1917, Naomasa was posthumously granted the courtesy title of junior third rank (
ju san-mi, 従三位) by
Emperor Taishō. == Personality ==