A History of Japan: From Mythology to Nationhood/The Warring States Period

The Sengoku period (戦国時代 Sengoku Jidai) or Warring States period in Japanese history was a time of social upheaval, political intrigue, and nearly constant military conflict that lasted roughly from the middle of the 15th century to the beginning of the 17th century. The name "Sengoku" was adopted by Japanese historians in reference to the Warring States period in Chinese history which preceded the unification of China. Likewise, the Sengoku period in Japan would eventually lead to the unification of political power under the Tokugawa shogunate. Although the Ashikaga shogunate had retained the structure of the Kamakura bakufu and instituted a warrior government based on the same social economic rights and obligations established by the Hōjō with the Jōei Code in 1232, it failed to win the loyalty of many daimyo, especially those whose domains were far from Kyoto. As trade with China grew, the economy developed, and the use of money became widespread as markets and commercial cities appeared. This, combined with developments in agriculture and small-scale trading, led to the desire for greater local autonomy throughout all levels of the social hierarchy. As early as the beginning of the 15th century, suffering and misery caused by natural disasters such as earthquakes and famines often served to trigger armed uprisings by farmers weary of debt and taxes. The Ōnin War (1467–1477), a conflict rooted in economic distress and brought on by a dispute over shogunal succession, is generally regarded as the onset of the Sengoku period. The "eastern" army of the Hosokawa family and its allies clashed with the "western" army of the Yamana, and fighting in and around Kyoto lasted for nearly 11 years, after which it spread to outlying provinces.

Gekokujō

The upheaval resulted in the further weakening of central authority, and throughout Japan regional lords, or daimyo, rose to fill the vacuum. In the course of this power shift, well established clans such as the Takeda and the Imagawa, who had ruled under the authority of both the Kamakura and Muromachi bakufu, were able to expand their spheres of influence. There were many, however, whose positions eroded and were eventually usurped by more capable underlings. This phenomenon of social meritocracy, in which capable subordinates rejected the status quo and forcefully overthrew an emaciated aristocracy became known as gekokujō (下克上?), which literally means "the underling conquers the overlord." One of the earliest instances of this phenomenon was Hōjō Sōun, who rose from relatively humble origins and eventually seized power in Izu province in 1493. Building on the accomplishments of Sōun, the Late Hōjō clan remained a major power in the Kantō region until its subjugation by Toyotomi Hideyoshi late in the Sengoku period. Other notable examples include the supplanting of the Hosokawa clan by the Miyoshi, the Shiba clan by the Oda clan, and the Toki by the Saito. Well organized religious groups also gained political power at this time by uniting farmers in resistance and rebellion against the rule of the daimyo. The monks of the Buddhist True Pure Land sect formed numerous Ikkō-ikki, the most successful of which, in Kaga Province, remained independent for nearly 100 years.

The Rise of Oda Nobunaga

Oda Nobunaga

During the last half of the 16th century, a number of different daimyo became strong enough either to manipulate the Muromachi bakufu to their own advantage or to overthrow it altogether. One attempt to overthrow the bakufu was made in 1560 by Imagawa Yoshimoto, whose march towards the capital came to an ignominious end at the hands of Oda Nobunaga in the Battle of Okehazama. In 1562, The Tokugawa clan who was adjacent to the east of Nobunaga's territory became independent of the Imagawa clan, and allied with Nobunaga. The eastern part of the territory of Nobunaga's was not invaded by this alliance. And, he moves the army to the west. In 1565, an alliance of the Matsunaga and Miyoshi clans attempted a coup by assassinating Ashikaga Yoshiteru, the 13th Ashikaga shogun. Internal squabbling, however, prevented them from acting swiftly to legitimatize their claim to power, and it was not until 1568 that they managed to install Yoshiteru's cousin, Ashikaga Yoshihide, as the next Shogun. Failure to enter Kyoto and gain recognition from the imperial court, however, had left the succession in doubt, and a group of bakufu retainers led by Hosokawa Fujitaka negotiated with Nobunaga to gain support for Yoshiteru's younger brother, Yoshiaki.

Nobunaga, who had prepared over a period of years for just such an opportunity by establishing an alliance with the Asai clan in northern Ōmi Province and then conquering the neighboring province of Mino Province, now marched toward Kyoto. After routing the Rokkaku clan in southern Omi, Nobunaga forced the Matsunaga to capitulate and the Miyoshi to withdraw to Settsu. He then entered the capital, where he successfully gained recognition from the emperor for Yoshiaki, who became the 15th Ashikaga shogun.

Nobunaga had no intention, however, of serving the Muromachi bakufu, and instead now turned his attention to tightening his grip on the Kansai region. Resistance in the form of rival daimyo, intransigent Buddhist monks, and hostile merchants was eliminated swiftly and mercilessly, and Nobunaga quickly gained a reputation as a ruthless, unrelenting adversary. In support of his political and military moves, he instituted economic reform, removing barriers to commerce by invalidating traditional monopolies held by shrines and guilds and promoting initiative by instituting free markets known as rakuichi-rakuza.

By 1573 he had destroyed the alliance of Asakura clan and Azai clans that threatened his northern flank, obliterated the militant Tendai Buddhists monastic center at Mount Hiei near Kyoto, and also had managed to avoid a potentially debilitating confrontation with Takeda Shingen, who had suddenly taken ill and died just as his army was on the verge of defeating the Tokugawa and invading Oda's domain on its way to Kyoto.

Even after Shingen's death, there remained several daimyo powerful enough to resist Nobunaga, but none were situated close enough to Kyoto to pose a threat politically, and it appeared that unification under the Oda banner was a matter of time.

Nobunaga's enemies were not only other Sengoku daimyō but also adherents of a Jōdo Shinshu sect of Buddhism who attended Ikkō-ikki. Their leader was Kennyo. He endured though Nobunaga kept attacking his fortress for ten years. Nobunaga expelled Kennyo in the eleventh year, but, by a riot caused by Kennyo, Nobunaga's territory took the big damage. This long war was called Ishiyama Hongan-ji War.

To suppress the Buddhism, Nobunaga supported Christianity. And, a lot of cultures were introduced to Japan by the missionary from Europe. Those things include new foods, new drawing methods, astronomy, geography, medical science, and new printing techniques.

Unification of Japan

After nearly a century and a half of political instability and warfare, Japan was on the verge of unification by Oda Nobunaga, who had emerged from obscurity in the province of Owari (present-day Aichi Prefecture) to dominate central Japan, when in 1582 Nobunaga himself fell victim to the treachery of one of his own generals, Akechi Mitsuhide. This in turn provided Toyotomi Hideyoshi, who had risen through the ranks from ashigaru (footsoldier) to become one of Nobunaga's most trusted generals, with the opportunity to establish himself as Nobunaga's successor. Hideyoshi eventually consolidated his control over the remaining daimyo and, although he was ineligible for the title of Seii Taishogun because of his common birth, ruled as Kampaku. When, in 1598, Hideyoshi died without leaving a capable successor, the country was once again thrust into political turmoil, and this time it was Tokugawa Ieyasu who took advantage of the opportunity. This topic will be discussed in more detail in the next chapter.

Notable People of the Sengoku Period

Daimyo

• Oda Nobunaga
• Toyotomi Hideyoshi
• Tokugawa Ieyasu

• Azai Nagamasa
• Chōsokabe Motochika
• Date Masamune
• Hōjō Sōun
• Ii Naotora
• Imagawa Yoshimoto
• Maeda Toshiie
• Miyoshi Nagayoshi
• Mōri Motonari
• Ōtomo Sōrin
• Saitō Dōsan
• Sanada Masayuki
• Shimazu Yoshihiro
• Tachibana Ginchiyo
• Takeda Shingen
• Uesugi Kenshin
• Ukita Hideie

Other notable individuals

• Akechi Mitsuhide
• Fukushima Masanori
• Fūma Kotarō
• Hattori Hanzō
• Honda Tadakatsu
• Ii Naomasa
• Ishida Mitsunari
• Kato Kiyomasa
• Maeda Keiji
• Miyamoto Musashi
• Mori Ranmaru
• Naoe Kanetsugu
• Oda Nobutada
• Saika Magoichi
• Sanada Yukimura
• Sasaki Kojirō
• Shibata Katsuie
• Shima Sakon