The Mikawa Ikkō-ikki occurred during the Sengoku period over approximately a six-months from Eiroku 6 (1563) to Eiroku 7 (1564).  This was an uprising by the Ikkōshū (followers of an offshoot of the Jōdo Shinshū sect affiliated with the Hongan Temple) in the western portion of Mikawa Province.  This did not extend to the powerful group of monks affiliated with the Sōtō sect in eastern Mikawa who were not under the governance of the Matsudaira family.

Overview

The Mikawa Ikkō-ikki, along with the Battle of Mikata-ga-hara and the Iga Crossing, is known as one the three great crises confronted by Tokugawa Ieyasu.  Many in his band of retainers joined the side of the monks which plainly showed the threat posed by religious followers to Ieyasu.

The Honshō Temple, the Jōgū Temple, and the Shōman Temple served as bases of the Hongan Temple religious band in Mikawa and were called the Three Temples of Mikawa.  In the era of Matsudaira Hirotada (the father of Tokugawa Ieyasu), the temples had special rights that prohibited entry or use by military governors (to preserve their autonomy from the provincial rulers).

Kūsei (the great-grandson of Rennyo) and tenth head of the Honshō Temple rallied the followers of the Hongan Temple to fight against their landlord, Matsudaira Ieyasu (later known as Tokugawa Ieyasu).  One account of the Ikkōshū in Mikawa notes:  “The Kohon sub-temple of the Ikkōshū (affiliated with the Honshō Temple in the village of Nodera in the Hekikai District) is off-limits to the military governors and comprises one of the three temples of the Ikkō sect (in Mikawa).”

The forces leading the uprising included the Three Temples of Mikawa, the Honshū Temple, in addition to the Kira clan (the military governors of Mikawa), the Arakawa clan, the Sakurai-Matsudaira clan, and the Ōkusa-Matsudaira clan.  Honda Masanobu, Hachiya Sadatsugu, and Natsume Yoshinobu under the command of the Anjō-Matsudaira clan also participated.  From the era when the Anjō-Matsudaira based at Anjō Castle gained prominence at the expense of the Iwatsu-Matsudaira clan (the main branch of the Matsudaira family), local elements of followers of Shin Buddhism came under their command with the most extreme being the Ishikawa clan with members at the Honshō Temple, triggering discord as the clan split between supporters of the temple versus those backing Ieyasu.

Origin of uprising

There are various theories regarding the origins of the uprising.  According to the account of the Ikkōshū of Mikawa, it first began at the Honshō Temple or the Jōkū Temple.  A historical account authored by Ōkubo Tadataka notes in 1562, Sakai Masachika, the lord of Nishio Castle, apprehended persons who illegally entered the Honshō Temple so, on the basis that the unauthorized entry violated the special rights of the temple prohibiting entry or use by military governors, the uprising erupted in the first month of 1563.

Alternatively, in 1563, Suganuma Sadayori, a retainer of the Matsudaira clan, was ordered to build a fortress near the Jōkū Temple.  The misappropriation of crops from the Jōkū Temple to provision the fortress triggered the uprising.  The existence of a retainer named Suganuma Sadayori, however, is uncertain.  According to an account from the Tōshō Shrine, retainers took unhulled rice from the Jōkū Temple whereupon Ikkō monks abruptly launched an uprising.

The Three Temples of Mikawa asserted their rights to prevent the military governors from entering their premises while Ieyasu sought to dilute the special rights of the religious bands as a step toward unifying control over Mikawa, leading to a deepening chasm between the two parties.  Violations of the special rights of the followers of the Ikkō sect in the province triggered the uprising after the heads of the Honshō Temple, the Jōkū Temple, and the Shōman Temple issued an appeal and summoned followers of the Hongan Temple to raid the fortress built by the Suganuma clan near the Jōkū Temple.  Retainers of the Matsudaira who were followers of Shin Buddhism along with the powerful gōzoku including the Kira clan and remnants of the Imagawa clan joined forces, launching an assault against the main base of the Matsudaira at Okazaki Castle.  This turn of events created a precarious situation for Ieyasu.

The Manshō sub-temple affiliated with the Takada offshoot of Shin Buddhism of the influential Myōgen Temple sided with Ieyasu owing to poor relations with the Hongan Temple.

One analysis points out that Sakai Tadanao of Ueno Castle rebelled in the sixth month of 1563 (or earlier), Ogasawara HIroshige of Terabe Castle rebelled prior to the tenth month of 1563, and Kira Yoshiaki of Tōjō Castle rebelled at the end of the tenth month of 1563.  The Ikkō-ikki can be confirmed to have occurred after an attack on Honda Hirotaka at Doi Castle in the twelfth month of 1563 (or earlier).  Moreover, there are no traces of communications or planning between the Sakai, Ogasawara, and Kira on a joint basis with the Ikkō-ikki or the retainers of Ieyasu who supported them.  When Ikkō-ikki forces advanced on Okazaki Castle, they stayed in their own territory and did not send troops to Okazaki.  The rebellions by the Sakai and Kira clans as well as by the Ikkō-ikki were both targeted at Ieyasu, but the two groups did not act in coordination with one another.

Status of Tokugawa retainers

• Honda Masanobu: Absconded after the war.  Became a wandering samurai and served Matsunaga Hisahide among others.  Later, through the offices of Ōkubo Tadayo, returned to service in an important role and became a senior retainer during the early period of the Edo bakufu.
• Honda Masashige: Participated along with his older brother, Masanobu.  Later, was pardoned and returned to service.  Despite contributions in battle, he absconded and, after serving Takigawa Kazumasu, Maeda Toshiie, and Gamō Ujisato, returned to service again.
• Watanabe Moritsuna: Pardoned and returned to service.  Later, served as an affiliate chief retainer of Tokugawa Yoshinao.  Counted among the Sixteen Divine Generals of the Tokugawa.
• Hachiya Sadatsugu: Surrendered and returned to service in 1564.  Counted among the Sixteen Divine Generals of the Tokugawa.
• Natsume Yoshinobu: Upon the fall of Yabane Castle (or, under another theory, Mutsuguri Castle), was apprehended by Matsudaira Koretada and later pardoned and returned to service following an ardent appeal by Koretada.
• Naitō Kiyonaga: Sentenced to confinement.  His son, Naitō Ienaga, became alienated from his father and served on behalf of the Tokugawa.
• Katō Noriaki: Absconded after the war.  After serving Ashikaga Yoshiaki (the fifteenth head of the Muromachi bakufu), served Hashiba Hideyoshi.  His son, Yoshiakira, gained stature under Hideyoshi.
• Sakai Tadanao: There is a theory that, prior to the outbreak of the Ikkō-ikki, he holed-up in his castle.  There are no traces of his connection to the ikki forces.  He resisted after the end of the uprising.
• Ishikawa Yasumasa: His father, Ishikawa Kiyokane, served as a representative of the followers of the Hongan Temple in Mikawa.  The Ishikawa clan maintained a deep relationship with the Ikkō monks.  Kiyokane’s wife was the younger sister of Ieyasu’s mother while Yasumasa and Ienari (siblings) were cousins of Ieyasu.  Owing to these family ties, Yasumasa’s eldest son, Ishikawa Kazumasa, changed his religious affiliation and, together with Ienari, served on behalf of Ieyasu.

Conclusion and aftermath

After prevailing at the Battle of Batōbara on 1/15 of Eiroku 7 (1564), Ieyasu stood in an advantageous position leading to a settlement and dissolution of the uprising.  According to a letter from Mizuno Nobumoto who participated in the mediation between the warring parties, in the spring of 1564, the parties reached a settlement and the province became peaceful.  Thereafter, in the fourth month of 1564, the Ogasawara clan obeyed Ieyasu while the Kira clan and Sakai Tadanao who continued their resistance were banished.

Among the bushi who participated in the uprising, some were caught in-between a sense of loyalty toward their lord and toward their religious beliefs.  Many of these bushi sought to return to the service of the Tokugawa so support for a continuation of the uprising waned.  At this time, the monk’s quarters at the Honshō Temple, along with the monastery at the Shōman Temple, burned down.  After having the Ikkō sect completely disbanded in the wake of their settlement, Ieyasu pressured the temples in Mikawa affiliated with the Hongan Temple to change their affiliations and, if they refused, destroyed them.

Regarding the suppression of the temples in Mikawa affiliated with the Hongan Temple, there is another view.  Amidst struggles with the defection of some of his retainers, Ieyasu issued an exemption order known as a tokuseirei to those retainers who stood by him, providing them relief from any of their debts to the Hongan Temple.  After the settlement with the Ikkō-ikki, the disposition of this order became an issue.  Mizuno Nobumoto, a facilitator of the settlement, requested the Honshō Temple to recognize at least a portion of the order but the temples in Mikawa affiliated with the Hongan Temple pushed back on the grounds that this violated the terms of the settlement.  This left Ieyasu caught between the terms of the settlement and the promises made to his retainers.  In the twelfth month of 1564 or thereafter he then began to suppress the temples in Mikawa affiliated with the Hongan Temple.

By 1583, nineteen years after the end of the uprising, the Hongan Temple was prohibited from operating in Mikawa.  Although Ieyasu imposed harsh measures against those affiliated with religious band, he was lenient toward those retainers who defected and thereby succeeded in raising the spirit of unity among the family members.  Some retainers, however, such as Honda Masanobu, absconded.

This uprising was triggered by followers of the Ikkō sect who drew-in members of the Tokugawa family and the band of retainers in a bid to thwart Ieyasu’s aim to garner control of the entire province of Mikawa.  As such, it served as one of the barriers that Ieyasu had to overcome to unify the province as a sengoku daimyō of the main branch of the Matsudaira family.