During the last half of the 16th century, a number of
daimyōs became strong enough either to manipulate the
Ashikaga shogunate to their own advantage or to overthrow it altogether. One attempt to overthrow the
bakufu (the Japanese term for the shogunate) 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 territory of Nobunaga was not invaded by this alliance. He then moved his army west. In 1565, an alliance of the
Matsunaga and
Miyoshi clans attempted a coup by assassinating
Ashikaga Yoshiteru, the 13th Ashikaga
shōgun. 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
shōgun. 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
Azai clan in northern
Ōmi Province and then conquering the neighboring
Mino Province, now marched toward Kyoto. After routing the Rokkaku clan in southern Ōmi, 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 and last Ashikaga
shōgun. Nobunaga had no intention, however, of serving the Muromachi
bakufu, and instead now turned his attention to tightening his grip on the Kinai region. Resistance in the form of rival
daimyōs, 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. The newly installed
shōgun Ashikaga Yoshiaki also was extremely wary of his powerful nominal retainer Nobunaga, and immediately began plotting against him by forming a wide alliance of nearly every
daimyō adjacent to the Oda realm. This included Oda's close ally and brother in-law
Azai Nagamasa, the supremely powerful
Takeda Shingen, as well as the monk warriors from the
Tendai Buddhists monastic center at
Mount Hiei near Kyoto (who became the first major casualty of this war as it was completely destroyed by Nobunaga). As the Oda army was bogged down by fighting on every corner,
Takeda Shingen led what was by then widely considered as the most powerful army in Japan and marched towards the Oda home base of
Owari, easily crushing Nobunaga's young ally and future
shōgun Tokugawa Ieyasu in the
Battle of Mikatagahara in 1573. However, as the Takeda army was on the cusp of obliterating the Oda–Tokugawa alliance,
Takeda Shingen suddenly perished, under mysterious circumstances. (Multiple suggestions for his demise include battlefield death from marksman, ninja assassination, and stomach cancer.) Having suddenly lost their leader, the Takeda army quickly retreated back to their home base in
Kai Province. With the death of
Takeda Shingen in early 1573, the "Anti-Oda Alliance" that
Ashikaga Yoshiaki created quickly crumbled as Nobunaga destroyed the alliance of the
Asakura clan and
Azai clan that threatened his northern flank, and soon after expelled the
shōgun himself from Kyoto. Even after Shingen's death, there remained several
daimyōs 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
daimyōs but also adherents of a
Jōdo Shinshū sect of Buddhism who were of the
Ikkō-ikki faction, led by
Kōsa. He endured though Nobunaga kept attacking his fortress for ten years. Nobunaga expelled Kennyo in the eleventh year, but, through a riot caused by Kennyo, Nobunaga's territory took the bulk of the damage. This long war was called the
Ishiyama Hongan-ji War. Nobunaga was highly interested in foreign cultures, especially those of western Europe. A significant amount of Western Christian culture was introduced to Japan by missionaries from Europe. From this exposure, Japan received new foods, a new drawing method, astronomy, geography, medical science, and new printing techniques. Most critically, trade with Europe provided Nobunaga's armies with new weapons, among them the matchlock rifle or arquebus. Nobunaga decided to reduce the power of the
Buddhist monasteries, and gave protection to
Christianity, although he never converted to Christianity himself. He slaughtered many Buddhist priests who resisted him, and burned their fortified temples. The activities of European traders and
Catholic missionaries (
Alessandro Valignano,
Luís Fróis,
Gnecchi-Soldo Organtino) in Japan saw one of the earliest relatively numerous increase of Europeans into the region. During the period from 1576 to 1579, Nobunaga constructed, on the shore of
Lake Biwa at
Azuchi,
Azuchi Castle, a magnificent seven-story castle that was intended to serve not simply as an impregnable military fortification, but also as a sumptuous residence that would stand as a symbol of unification. Having secured his grip on the Kinai region, Nobunaga was now powerful enough to assign his generals the task of subjugating the outlying provinces.
Shibata Katsuie was given the task of conquering the
Uesugi clan in
Etchū,
Takigawa Kazumasu confronted the
Shinano Province that a son of Shingen,
Takeda Katsuyori governed, and
Hashiba Hideyoshi was given the formidable task of facing the
Mōri clan in the
Chūgoku region of western Honshū. In 1575, Nobunaga won a significant victory over the Takeda clan in the
Battle of Nagashino. Despite the strong reputation of Takeda's samurai cavalry, Oda Nobunaga embraced the relatively new technology of the
arquebus, and inflicted a crushing defeat. The legacy of this battle forced a complete overhaul of traditional Japanese warfare. In 1582, after a protracted campaign, Hideyoshi requested Nobunaga's help in overcoming the resistance of the Mōri clan. Nobunaga, making a stop-over in Kyoto on his way west with only a small contingent of guards,
was attacked by one of his own disaffected generals,
Akechi Mitsuhide, and committed suicide. ==Hideyoshi completes the unification==