The Sengoku period was a chaotic time full of social upheaval, political intrigue, and nearly constant military conflict, that lasted roughly from 1467 to 1603. Lots of events happened and many people were involved, but this page nevertheless attempts to list some of the major starting points and turning points in the Sengoku period as well as list some of the important people that took part in these events.
The Onin war is said to be the beginning of the Sengoku period. What started it all was a dispute over the succession of the Shogun of Japan. Japan had always had an Emperor, but real political power often lay in the hands of the Shogun, while the Emperor remained the ceremonial ruler of Japan.
At the start of the Sengoku period, the Shogun came from the Ashikaga clan, but the Ashikaga Shogunate was weak compaired to other previous Shogunates. In essence the Ashikaga were themselves puppet rulers in the hands of the Hosokawa clan, but the Hosokawa clan had no effective sway over the Ashikaga. Effectively there were two branches of the Ashikaga, one based at Kyoto and another based at Kamakura in the Kanto region. The Hosokawa clan was primarily based in the Kinai region around the city of Kyoto, while Ashikaga power in the Kanto region was backed up by the Uesugi clan.
The trouble was that Shogun Ashikaga Yoshimasa was getting old and wanted to retire and pursue a career in the arts, but he was initially without an heir of his own. So that meant Shogun Ashikaga Yoshimasa called in his younger brother Ashikaga Yoshimi. This younger brother was forced to abandon the life of a monk and was appointed heir to Ashikaga Yoshimasa. Ashikaga Yoshimi was a member of the "Jodo Shinshu" sect also known as the "Pure Land Buddhism" sect and it is generally believed that the two brothers were eachother's opposites in character and did not get along very good. The younger brother Ashikaga Yoshimi was backed by Hosokawa Katsumoto, who was in reality the real power behind the Ashikaga Shogunate.
Hosokawa Katsumoto had one powerful political rival, namely his father-in-law by the name of Yamana Sozen, who was a member of the Yamana clan, a powerful clan based in the provinces just to the northwest of Kyoto. Like the Ashikaga brothers these two powerful rivals were their exact opposites in character. Hosokawa Katsumoto is said to have had a calm and poised personality, in stark contrast to Yamana Sozen, who was nicknamed "the Red Monk", because he had a notoriously bad temper.
What happened next was an event that neither rival, nor the Ashikaga clan, had foreseen. In 1465 a son of Ashikaga Yoshimasa named Ashikaga Yoshihisa was born. Yamana Sozen decided to back this infant son as heir to the throne much to the dismay of Hosokawa Katsumoto. Meanwhile Yamana Sozen made several visits to Ashikaga Yoshimasa to establish political relations between the two and possibly also to stir up sibling rivalry between the two Ashikaga brothers. Tensions started to flare between the Hosokawa backed faction and the Yamana backed faction. By 1466 each side had set up a huge army inside Kyoto and a standoff ensued.
Somewhere in 1467 Yamana Sozen was officially declared a rebel in a political move, that is likely to have been instigated by the Hosokawa backed faction. A sudden fire erupted in the Shokoku-ji temple complex on the northside of Kyoto and this fire would ignite the Onin war, as both sides put the blame squarely with the other. Fights ensued inside the city of Kyoto destroying huge portions of the city in the process. This destruction of Kyoto put a huge strain on the Imperial treasury, further weakening central authority. Though both Yamana Sozen and Hosokawa Katsumoto were already dead in 1473, fighting still went on. Peace finally came about in 1477 when the two sides had fought eachother to a standstill. By now Kyoto lay in complete ruins. In the end neither side had the strength to pursue the war any further, instead however war spread to the outlying provinces in Japan as in the absence of a strong central authority, lesser prominent clans found ways to feud with their neighbouring rivals.
With the city of Kyoto in ruins, the situation in the province of Yamashiro turned dire. Taxes skyrocketed and increased the burden on the poor peasants in Yamashiro province. This rebellion gradually became religiously inspired, when it received the backing of some powerful monasteries inside Yamashiro province, many of which had ties with the now already infamous Jodo Shinshu sect. This rebellion became particularly troublesome to the Hatakeyama clan, because they had territories to the north and south of Yamashiro province, which meant that their territory would effectively be cut in two. The Hatakeyama branch inside Noto province also had troubles of internal dissent, further complicating matters. Some members of the Hatakeyama branch in Noto wanted to remain allied to the Hosokawa clan, while others were keen to make peace.
In reality the military power in the northern parts of the Hatakeyama territory was primarily in the hands of the Togashi clan, who were based in the provinces of Kaga and Echizen, just to the south of Noto province. This meant that Togashi Masachika was forced to vacate to Kyoto to support the Hosokawa clan in their war against the Yamana clan. The rebellion inside Yamashiro was eventually put down, with many of the rebels fleeing to other adjacent provinces, including such provinces as Echizen and Kaga. That meant that far from the rebellion being put down, it simply spread to other places in Japan.
With Togashi Masachika absent from his headquarters at Kanazawa in Kaga province, peasants, monks and some members of the Togashi household saw an opportunity to take advantage of this situation and rebelled. This rebellion succeeded where prior revolts had failed. With the taciturn and fickle political support of the spiritual leader of the Jodo Shinsu sect by the name of Rennyo, a peasant kingdom was formed in Kaga province that would last for nearly a century until it was destroyed by Oda Nobunaga in 1580.
This manner in which lowly peasants, monks and some lower ranking Samurai would revolt and effectively take over became known as "Gekokujo", or "the low overcomes the high".
One archetypical example of "Gekokujo" is how Ise Shinkuro got himself a realm of his own and ultimately became known as Hojo Soun. Over the course of his life, he would rise from the ranks of a lowly Ronin, to become one of the most powerful "Daimyo" of the Sengoku period.
Ise Shinkuro started out as a mere "Ronin" or "wave man", a term used for Samurai without a master. His family was a side branch of the more illustrious Ise family who worked for the Ashikaga Shogunate. His sister was married to Imagawa Yoshitada of the illustrious Imagawa clan, a clan that had important family connections with the Ashikaga clan. When Imagawa Yoshitada died in 1476, Ise Shinkuro became a vassal of the Imagawa clan. Ise Shinkuro mediated in a succession dispute between the supporters of Imagawa Yoshitada's son, Imagawa Ujichika and Imagawa Yoshitada's cousin, Oshika Norimitsu. This proved to be a temporary peace. When Oshika Norimitsu again attempted to gain control of the Imagawa clan, Hojo Soun came to Imagawa Ujichika's defense and killed Oshika Norimitsu in 1487. Hojo Soun was rewarded for this feat by Imagawa Ujichika with Kokukuji castle.
Now that Ise Shinkuro finally had a small territory he could call his own, he slowly but gradually started to expand it. In 1493 he took control of Izu province, while avenging a wrong committed by a member of the Ashikaga clan. After this event Ise Shinkuro became de facto independent of the Imagawa clan and started to become one of the first true Sengoku "Daimyo", or "great names" of the Sengoku period.
Ise Shinkuro saw another opportunity to expand his realm, when Omori Ujiyori who held Odawara in Sagami province died in 1494. His son Omori Fujiyori took over after the death of his father. When the "Kanto Kanrei" Uesugi Sadamasa also died in 1494, the young Omori Fujiyori was now also without a powerful overlord. Ise Shinkuro was quick to avail himself of this new opportunity. He presented himself to the young lord of Odawara as a friend and father figure, bringing him such expensive gifts as his treasury would allow. In 1495 Ise Shinkuro used the pretext of a large deer hunt, to bring his soldiers deep into Omori territory. He captured Odawara quickly, forcing Omori Fujiyori to flee to Okazaki. By 1496 Ise Shinkuro allied with the Ueda clan and the Ota Clan, the latter had already lost Edo castle in Musashi province to the Uesugi clan prior to these events. By 1504 Ise Shinkuro was stuck in a full scale war with the Uesugi clan over Sagami province.
When Ashikaga Yoshihisa died childless in 1489 on a battlefield in the south of Omi province, Hosokawa Masamoto, the son of Hosokawa Katsumoto, supported the nomination of Ashikaga Yoshizumi as successor. Hosokawa Masamoto probably reasoned that this move would bring Hosokawa Masanaga back to power and thus allow the Hosokawa clan to retake the office of the Shogun's deputy in Kyoto, or Kyoto Kanrei.
The other contender for the position of Shogun was Ashikaga Yoshitane, who was backed by Hatakeyama Masanaga, a rival of Hosokawa Masamoto. Hatakeyama Masanaga had troubles of his own however and Ashikaga Yoshitane was forced to aide Hatakeyama Masanaga in putting down a rebellion of other Hatakeyama family members. Hosokawa Masamoto got wind of this rebellion and decided to support the rival Hatakeyama branch in opposition to Hatakeyama Masanaga. Hosokawa Masamoto's army managed to defeat the army of Ashikaga Yoshitane and Hatakeyama Masanaga. Hatakeyama Masanaga would commit suicide after this defeat, the first infamous case of "Seppuku" of a Daimyo. Meanwhile Ashikaga Yoshitane was captured and became a prisoner in Kyoto of Hosokawa Masamoto. Hosokawa Masamoto then successfully manouvered Ashikaga Yoshizumi into becoming the new Shogun. Ashikaga Yoshizumi thus became Hosokawa Masamoto's puppet Shogun.
The problem was that Hosokawa Masamoto himself had no children and so adopted Kujyo Sumiyuki and Hosokawa Sumimoto as his sons. The retainers of the Hosokawa clan then disputed for very long, who of the two adopted sons should be the successor of the Hosokawa. In the year of 1504, Masamoto eliminated Yakushiji Motoichi who backed Hosokawa Sumimoto, whom Hosokawa Masamoto did not want as successor. This did not end the succession dispute however, and in 1506 another one of Hosokawa's retainers raised an army. Miyoshi Yukinaga of the Miyoshi clan, one of the retainers of the Hosokawa clan in Awa province on the island of Shikoku, not to be confused with Awa province on the island of Honshu, marched on Hosokawa Masamoto. Threatened by the Miyoshi clan, Hosokawa Masamoto, then chose someone else as his successor. Kosai Motonaga, along with Kujyo Sumiyuki next broke into the house of Hosokawa Masamoto and killed him while he was taking a bath.
Meanwhile the troubles and wars in the Kanto region were not over.
After some early setbacks, by 1504 Ise Shinkuro started to prevail over the Uesugi led alliance. In 1512 he managed to capture the old Shogunal capital of Kamakura.
Next Ise Shinkuro set his sights on the castle of Arai, which was held by Miura Yoshiatsu. He took it in 1516 in a short siege.
By now Ise Shinkuro had carved out a considerable realm of his own. In 1519 Ise Shinkuro finally died and was succeeded by his son. His son wanted to emulate some sort of emaculate pedigree and took on the Hojo family name, known after the famed Hojo regency, even though he bore no relationship to this clan, only his wife was a remote descendant of this clan. Hojo Ujitsuna as he became known posthumously rewarded his father Ise Shinkuro with the name Hojo Soun.
Ashikaga Yoshitane regained the position of Shogun in 1508 after the power struggle in the Hosokawa clan that caused the death of Hosokawa Masamoto. Ashikaga Yoshitane was backed in his bid for Shogun by Ouchi Yoshioki of the Ouchi clan. The Ouchi clan were a powerful clan based on the southern most tip of the Tsugoku peninsula, a peninsula on the western most part of the island Honshu.
Ouchi Yoshioki raised an army in 1507 and marched on Kyoto. On his way to Kyoto he fought a great number of other powerful Samurai families along the way. He removed the puppet shogun Ashikaga Yoshizumi. Ouchi Yoshioki was awarded the fourth rank in the Imperial court for his efforts. He remained in Kyoto and continued to back Ashikaga Yoshitane, both military and financially, until 1518 when he was forced to return to his family's home in Yamaguchi.
Ouchi Yoshioki was forced to return home in 1518, because his son Ouchi Yoshitaka mishandled affairs at home. Ouchi Yoshitaka was in a constant strife with Amako Haruhisa of the Amako clan over control of Aki province, and this war was not going well for the Ouchi clan. The problem for the Ouchi clan was that they were essentially waging a two-front war, because to the south of the Ouchi domain lay Kyushu island. The northern parts of Kyushu island were then held by Shoni Sukemoto of the Shoni clan, yet another powerful Daimyo clan, and an enemy of the Ouchi clan.
Further complicating matters for the Ouchi clan was the fact that they were still busy fighting the remnants of the Hosokawa clan. This war between the Ouchi and the Hosokawa clans was not confined to Japan alone. In 1523 Shoni forces briefly fought Hosokawa forces in the port of Ningpo, which was located in China. Fed up with this incessant strife amongst the Japanese clans and not wanting to get dragged into this civil war, the Chinese Emperor for some years closed off trade with Japan in 1525. Clans like the So clan, that relied heavily on this trade with China, were now forced to reckon with a sudden drop in their income, and in desperation turned to piracy. These Japanese pirates became infamously known as the "wokou", a corruption of the Chinese words for "wo" (a derogatory name for Japanese, literally meaning dwarf nation) and "kou", which meant "bandit".
In the absence of his puppeteer Ouchi Yoshioki, Ashikaga Yoshitane was now tied up in the Kyoto intrigues alone. In 1520 Hosokawa Takakuni finally forced Ashikaga Yoshitane to flee to Awaji island, and in 1523 Ashikaga Yoshitane died in Awa province on the island of Shikoku. All of this meant that in 1521 Ashikaga Yoshiharu, would be installed as the next Ashikaga Shogun, by Hosokawa Takakuni.
The rebellious Miyoshi clan however marched on Kyoto in 1528 and briefly took the capital, also forcing Hosokawa Takakuni to flee the capital.
Meanwhile back on the Tsugoku peninsula, the Ouchi were still waging war against the Amako clan based in Izumo province. What intensified this war in the Tsugoku peninsula was the discovery of large amounts of silver at a place called Iwami which lay near Ozumi province, right at the effective border of the Amako domain.
Sandwiched between the powerful Amako and Ouchi clans, was the Mori clan, who had their headquarters established in Aki province. From 1516 onwards Mori Motonari became the head of the Mori clan, he carefully led the clan by balancing between actions and diplomacy.
What happened next is that Ouchi Yoshitaka led an invasion into the Amako domain in 1541, in an effort to capture the Iwami silvermine. This invasion ended up in a complete disaster. As a result of this failed invasion the Ouchi position weakened and some of their retainers rebelled. Mori Motonari now saw an opportunity to rid himself of the Ouchi clan and allied himself with the Shoni clan. In a combined effort the Mori and Shoni utterly destroyed the Ouchi clan military power and by 1560 the Mori clan eclipsed the Ouchi clan.
Meanwhile the "Ikki" or peasant rebels had not remained silent and in 1496 master Rennyo retired to the area of Ishiyama Hongan-ji (nowadays located at the modern city of Osaka), where he finally died in 1499.
When the Yamashina Mido temple was destroyed by lay monks of the rival Nichiren sect in 1532, the effective headquarters of the Jodo Shinshu sect was transferred to Ishiyama Hongan-ji. Over the following decades it would evolve into a powerful fortified temple complex, and was considered a virtually impregnable fortress by many samurai.
The Shoni clan managed to back off the encroachment into their territory by Ouchi forces with help of the Otomo clan. Around 1530 it seemed that Kyushu island would finally see some semblance of unity under the rule of the Shoni clan, however Shoni Sukemoto died in 1532. Shoni Tokinao took over, but he suffered a rebellion of his retainer Ryuzoji Takanobu in yet another act of what could be called "Gekokujo", and by 1559 the Shoni clan was utterly destroyed. It seemed like the Ryozuji would battle it out with the Otomo clan for control of Kyushu island, but yet another event took place that would ultimately change the balance of power on the island of Kyushu.
Marginalised by powerful clans like the Ouchi, Otomo and Ryuzoji, were other clans like the Arima. Some of whose rulers were resentful of the fact that their families had been supplanted.
To the south of all this complicated mess lay the city of Kagoshima in the province of Satsuma. Here in 1526 Shimazu Takahisa had taken over the reigns of the Shimazu clan and he slowly, but steadily started to expand his domain and came into frequent conflict with the Otomo clan.
What happened next is that a ship carrying Portuguese sailors got shipwrecked off the coast of the island of Tanegashima. Tanegashima was one of the northern most islands in Ryukyu archipelago, a then semi-independent kingdom, just to the south of Satsuma province (the Shimazu domain). This event marked the beginning of the first European contact with the Japanese. Shimazu Takahisa met with Francis Xavier in 1549. Francis Xavier was a Jesuit missionary who started preaching the Christian faith in Japan.
The Portuguese weren't interested in matters of faith alone, and also started trading with the Japanese. They also brought with them new weapons such as arquebuses. The Japanese were familiar with gunpowder, through the Chinese, but these Portuguese arquebuses were more effective missile weapons than prior Chinese weapons of such sort and what is more, they could be mass produced with ease.
Use of these new firearms started to spread across Japan. Clans like the Arima for instance converted to Christianity in order to acquire these new weapons, but the first to use them on the battlefield was Shimazu Takahisa. Soon afterwards Otomo Sorin also converted to Christianity.
Many of us tend to think of the quintessential Japanese Samurai as carrying "Katana" or other kinds of swords and dispatching their enemies by lopping off the heads of their enemies with these swords. While some Samurai certainly did use "Katana" in battle, most swords were expensive items of prestige and rarely used. In fact most early Sengoku samurai still fought with bows on horseback. By the middle of the Sengoku period large numbers of "Ashigaru" or "foot soldiers" carrying spears were drafted into the ever larger Samurai armies, with the discovery of the arquebus, known by the Japanese as "Tanegashima", named after the island where the Portuguese had shipwrecked, many of these Ashigaru switched from spears to arquebuses. Thus by the late Sengoku period the quintessential Samurai was not the rider carrying Katana, but the lowly foot soldier carrying arquebuses.
By the middle of the Sengoku period, the power of the Ashikaga Shogunate had truly waned and many of the illustrious clans that had supported the Shogunate had largely been destroyed or severely weakened.
The Uesugi clan which had during the Onin war split into three family branches, attempted to turn the tide. The Ogigayatsu branch assembled a massive army that is estimated to have numbered 85,000 men and attempted to take back Kawagoe castle, which had previously been taken from them by the Hojo clan.
The Kawagoe garrison numbered perhaps some 3,000 men. Though strongly outnumbered, Hojo ninja spies informed the Hojo forces, that Ashikaga Tsunanari had relaxed their vigilance due to their overconfidence in victory.
Next, the Hojo relief force, estimated to have numbered perhaps some 8,000 men, attempted a risky tactic, and under the cover of darkness attacked the Uesugi army. It worked and this defeat of the Uesugi army lead to the near extinction of the Uesugi clan. The next series of battles also failed, and by 1551 the Uesugi family line was effectively destroyed.
Nagao Kagetora was a member of the Nagao clan based in Echigo province. The Nagao had previously submitted to the Uesugi clan in an effort to halt the power of the Ikko Ikki, who were by then getting ever closer to the borders of Echigo province. This essentially made the Nagao clan vassals of the Uesugi clan. This Nagao Kagetora was adopted into the Uesugi family and took the name Uesugi Kenshin and he would later become famous as one of the finest warlords of the Sengoku period.
Meanwhile a young Daimyo by the name of Oda Nobunaga grew up in Owari province. Oda Nobunaga was nicknamed the "fool of Owari", because he was rumoured to behave in outrageous manners, unbecoming of his status. His father had unexpectedly died in 1551, and Oda Nobunaga spent his late teens, eliminating opposition to his rule within the clan and his retainer band. By 1559 his rule was undisputed throughout Owari province, but his power was minor compaired to that of other prominent warlords at that time.
Imagawa Yoshimoto who was married to the sister of Takeda Shingen, had through this marriage cemented an alliance with the Takeda clan. The Imagawa clan were also related to the Hojo clan, who had initially been their vassals, and so Imagawa Yoshimoto also managed to broker an alliance with the Hojo clan. With his back secured, Imagawa Yoshimoto turned his attention on Owari province.
He amassed a huge army of perhaps some 35,000 soldiers and started to move this army towards Owari province. The initial pretext given for this move was that Imagawa Yoshimoto wanted to back the frail Ashikaga Shogunate in Kyoto, but in reality everyone knew he was bent on conquering Owari province to expand his domain.
Oda Nobunaga had perhaps some 2,500 soldiers. Nearly everyone, including some of Oda Nobunaga's own retainers, expected Oda Nobunaga to be defeated, because his forces were hugely outnumbered. Imagawa Yoshimoto ordered his vassals, which included the then largely unknown Matsudaira Takechiyo, to lay siege to the border forts of the Oda clan, while the main army moved further into Owari province. With the border forts secured and taken over, the main body of the Imagawa army moved into Owari province and set camp near a small village called Okehazama. Oda Nobunaga knew this area, as he spent most of his early youth in the Owari countryside and he was familiar to the terrain and the weather.
Confident that victory was in their hands, the Imagawa army relaxed their guard in the hot summer afternoon and some soldiers started drinking sake and dancing in celebration of their recent victories.
Nobunaga left a small force at a nearby temple with a large number of banners, to give the impression that this was the location of his main force. Meanwhile, Oda's main force, about 1,500 men, moved through the forest undetected to the rear of the Imagawa army. As they moved towards the Imagawa camp an afternoon thunderstorm helped to keep the Oda army undetected.
When the storm passed, Nobunaga's men poured into the camp from the north, and the Imagawa warriors lost all discipline and fled from the attackers. This left their commander's tent undefended, and the Oda warriors closed in rapidly. Imagawa Yoshimoto, unaware of what had transpired, heard the noise and emerged from his tent shouting at his men to quit their drunken revelry and return to their posts. By the time he realized, moments later, that the samurai before him were not his own, it was far too late. He deflected one samurai's spear thrust, but was beheaded by another.
With Imagawa Yoshimoto dead, many of his former vassals started to rebel and gradually switched sides towards Matsudaira Takechiyo. Matsudaira Takechiyo whose son was still held captive by the Imagawa clan, made a secret alliance with the Oda clan. After he captured the castle of Kaminojo, he exchanged the captives with his son and wife. With his hands freed by the exchange, Matsudaira Takechiyo married Oda Tokuhime, the daughter of Oda Nobunaga to further cement the alliance.
As Matsudaira Takechiyo aided the Nobunaga clan and he gradually started to expand his power, he enlisted the help of many notable Samurai, such as: the brilliant general Honda Tadakatsu, the great Ii Naomasa and the legendary Hattori Hanzo. In 1567 Matsudaira Takechiyo changed his name to Tokugawa Ieyasu.
A few decades earlier the Takeda had launched invasions into Shinano province from their headquarters located in Kai province. These invasions displaced some notable Daimyo clans, who in turn sought the help of the Uesugi clan. This sparked a feud between the Uesugi and the Takeda that would last decades. With Imagawa busy fighting in 1560 and with the Hojo clan locked in a feud with the Chiba clan, the Takeda clan saw yet another chance to renew their age old feud with the Uesugi and wage war on their bitter rivals. The Takeda clan were by then lead by the brilliant Daimyo known by the name of Takeda Shingen, nicknamed the "tiger of Kai". Equally brilliant was Uesugi Kenshin, who was nicknamed the "dragon of Echigo".
The fourth battle of Kanawakjima was again fought in the plains of Kanawakajima in the north of Shinano province on the banks of the Chikuma river. Unlike the previous battles and the fifth battle, this battle would result in heavy casualties on both sides. Both sides deployed about equal number of men, Uesugi had about 18,000 and Takeda's force is estimated to have numbered about 20,000 men. The battle became reknowned because both sides used clever tactics and interesting formations. The battle also became famous in another way, because it was rumoured to be the one battle where the two Daimyo actually fought, face to face. It was one of the last great battles in which both forces used a large number of cavalry. In the end though it proved to be an indecisive battle.
Due to the large amount of casualties inflicted on both sides, it bought the Oda-Tokugawa alliance time to concentrate their efforts on taking on the Ikko Ikki.
With the death of Imagawa Yoshimoto, and with Takeda busy fighting the Uesugi clan, the way was free for Oda Nobunaga to conquer Mino and Omi province. The only provinces that lay between Owari and Yamashiro. Oda Nobunaga did just that.
Mino province was at that time occupied by the Saito clan. Prior to the battle of Okehazama Oda Nobunaga had already seriously weakened the Saito clan. He had done this through a clever scheme. Oda Nobunaga was in fact married to the daughter of Saito Dosan, who was known by the name of Nohime. It became apparent that she was spying on Oda Nobunaga and would relay information to her maiden clan Saito, a fact not at all uncommon in those days. Oda Nobunaga provided her with false information about two servants plotting to destroy the Saito clan. Her father had both men executed and thus weakened himself by eliminating those loyal to him. With his remaining retainers alienated from him, they rose up to Saito Dosan in 1556 and killed him in a coup. The Saito power now lay in the hands of Saito Yoshitatsu.
Saito Yoshitatsu suddenly died of illness in 1561. His son Saito Tatsuoki was a much less effective ruler then his father had been. Oda Nobunaga started to convince Saito retainers to abandon their incompetent and foolish master, and this significantly weakened the Saito clan. Eventually an attack was mounted on Inabayama castle in 1567 and the castle captured. Saito Tatsuoki was sent into exile. With Mino province now squarely in hands of Oda Nobunaga he moved on to Omi province.
Oda Nobunaga had his forces lay siege to the castles of Odani and Yokoyama, which belonged to the Asai and Asakura clans.
In reaction to these sieges Asai and Asakura forces sallied forth and fought a pitched melee battle at Anegawa in Omi province. Oda Nobunaga used 500 arquebusiers in this battle, but most heads were taken by the allied Tokugawa clan.
The subsequent conquest of Omi province meant, that the "Ikko Ikki" were the last force that stood between Oda Nobunaga and the city of Kyoto. Oda Nobunaga next turned his attention towards eliminating the Ikko Ikki threat.
With Hojo Ujiyasu dead in 1571, the fortunes for the Hojo clan also declined. With his death a great military strategist was lost for the Hojo clan.
Now all that essentially remained between Oda Nobunaga and his undisputed rule over Japan, were the last remnants of the "Ikko Ikki". The only three clans capable of putting a halt to this were the Takeda clan, the Uesugi clan and the Mori clan.
Takeda Shingen knew this and he sought peace with the Uesugi clan, so he could contend with Oda Nobunaga.
It is not known exactly why, but Uesugi Kenshin accepted this cease of hostilities. That meant that Takeda Shingen was free to wage war on the Oda-Tokugawa alliance. Fortunately for Oda Nobunaga, Takeda Shingen suddenly died of illness in 1573.
Oda Nobunaga knew that the "Ikko Ikki" controlled all the access routes towards Kyoto. To defeat them would be vital to securing the way towards Kyoto. The elimination of the Ikko Ikki turned into a long and protracted campaign, that ended with the destruction of Ishiyama Hongan-ji in 1580, the last Ikko Ikki held fortress to fall into the hands of Oda Nobunaga.
Just to the south of the route from Owari province through Omi province onwards to Kyoto lay the island of Nagashima, which was held by "Ikko Ikki". This would be Oda Nobunaga's first target and the way the battle was fought provided an insight in what was to come.
Nagashima was located in a string of river islands and fortresses and evidentially was difficult to capture. Oda Nobunaga had already launched two previous assaults. The first attack failed when the peasants opened a dike, with the subsequent flood drowning many of Oda's men. The second attack failed when the arquebuses were rendered useless due to a heavy downpouring of rain. The third and last attack ultimately succeeded when fire-arrows set fire to the defensive works of the "Ikko Ikki". With the "Ikko Ikki" surrounded on all sides and thus not able to flee, many rebels burned to death in the fires. It is reckoned that some 20,000 people died in that siege.
With Nagashima out of the way, all that remained was Ishiyama Hongan-ji.
Takeda Katsuyori took over as leader of the Takeda clan, but he was not as great a military strategist as his father had been.
Takeda forces first took Mikatagahara in Mikawa province, and in the battle of Mikatagahara, the reknowned Takeda cavalry resoundedly defeated Tokugawa Ieyasu.
Next the battle went to Nagashino. Oda Nobunaga send about 15,000 troops and Tokugawa Ieyasy send about 12,000 troops to break the siege on Nagashino.
Seeking to protect his arquebusiers, which he would later become famous for, Oda Nobunaga built a number of wooden stockades, setting up his gunners to attack the Takeda cavalry in volleys. The stockades served to blunt the force of charging cavalry, provide protection from sword blows and spear thrusts, and provide limited protection from arrows. Ports or gates in the staggered and overlapping stockades were positioned to channel the cavalry charges into lanes where they would be vulnerable to further gunfire, arrows, and sword and spear thrusts from the stockade's defenders. There were approximately three gunmen for every four Takeda mounted samurai.
This tactic of rotating gunfire behind screens worked effectively and broke the back of the elite Takeda cavalry. It is estimated that about 10,000 Takeda men were killed in the battle, including 8 of the 24 famous Takeda generals. The surviving Takeda forces fled home to Kai province.
With the Takeda clan military power effectively eliminated, Oda Nobunaga now moved to consolidate his recently won territory.
The campaign against the "Ikko Ikki" had taught Oda Nobunaga a valuable lesson of the effectiveness of good defensive works and how it could it weaken the offensive strength of an army.
Oda Nobunaga decided to build a huge castle for himself that would be his new headquarters. He chose a location on the shores of lake Biwa, it was to be known as Azuchi. It took three years to complete his magnificent castle.
With the Takeda effectively out of the way after the battle of Nagashino, only two powerful clans were left, that could pose a serious threat to the plans of unification of Japan for Oda Nobunaga, namely the Uesugi clan and the Mori clan. Fortunately for Oda Nobunaga, Uesugi Kenshin died in 1578. Some historians believe that Uesugi Kenshin likely died of causes brought on by stomach cancer (apparently he bleed to death whilst taking a dump in his latrine). His supposed stomach cancer may have been brought about by his excessive drinking of sake (he was reputed to be an alcoholic).
By 1580 Ishiyama Hongan-ji, the last fortress held by the "Ikko Ikki" had been destroyed. Oda Nobunaga now ordered Takigawa Kazumasu to watch the Hojo, while Shibata Katsuie invaded Echigo province, which had been formerly held by the Uesugi clan. Meanwhile Niwa Nagahide prepared to invade Shikoku island and Toyotomi Hideyoshi was ordered to launch a military campaign against the Mori clan. Oda Nubonaga stayed put at Honno-ji near Kyoto to coordinate the campaigns. At the same time he called on his ally Tokugawa Ieyasu to tour the Kansai region in celebration of the demise of the Takeda clan. When Toyotomi Hideyoshi called for reinforcements for the siege of Takamatsu, presumably to humble himself in front of the other Oda vassals, who often were envious of him (Toyotomi Hideyoshi had originally been a lowly sandal bearer), this left Oda Nobunaga protected by only a handful of servants. What happened next shocked all of Oda Nobunaga's loyalists.
Akechi Mitsuhide was also one of Oda Nobunaga's generals. He is believed to have been related to the Toki clan of Mino province. A clan that had been Daimyo of Mino province prior to ascend of the Saito clan. Before serving Oda Nobunaga, Akechi Mitsuhide had served Ashikaga Yoshiaki after Asakura Yoshikage. Although Oda Nobunaga rarely put too much trust in his retainers, he particularly trusted Shibata Katsuie, Toyotomi Hideyoshi, and Akechi Mitsuhide. Akechi Mitushide was the first vassal, who received a castle from Nobunaga. After Mitsuhide received Sakamoto he moved to pacify the Tamba region by defeating several clans such as the Hatano clan and the Isshiki clan of Tango province. Akechi Mitsuhide also received Kamiyama castle and the Tanba region.
In 1579 Akechi Mitsuhide captured Yakami castle from Hatano Hideharu by promising Hatano Hideharu peace terms. This accomplished Akechi Mitsuhide's goal, although Oda Nobunaga betrayed the peace agreement and had Hatano Hideharu executed. According to some folk stories, this displeased the Hatano family, and a short while later several Hatano retainers murdered Akechi Mitsuhide's mother.
It is not precisely known why Akechi Mitsuhide chose to betray Oda Nobunaga, but some historians reason that the betrayed peace agreement with the Hatano clan and the subsequent murder of Akechi Mitsuhide's mother may have had something to do with it.
Akechi Mitsuhide was ordered by Oda Nobunaga to also aide Toyotomi Hideyoshi at the siege of Takamatsu. Upon receiving the order, Akechi Mitsuhide returned to Sakamoto Castle and moved to his base in Tamba province. Around this time, he had a session of "Renga" with several prominent poets, where he made clear his intentions to rebel.
Next Akechi Mitsuhide led his army to Kyoto. Before dawn the Akechi army had Honno-ji surrounded. Oda Nobunaga and his servants and bodyguards resisted, but they realized it was futile against the overwhelming numbers of Akechi troops. Oda Nobunaga committed suicide and the temple was set on fire by his young page.
After capturing Honno-ji, Mitsuhide attacked Oda Nobutada, heir to Oda Nobunaga, who also committed suicide.
After trying to persuade Oda vassals in the vicinity to recognize him as the new master of former Oda territories, Akechi Mitsuhide entered Azuchi Castle and began sending messages to the Imperial court to boost his position and force the court to recognize him as well.
When Toyotomi Hideyoshi heard of the news, he quickly made peace with the Mori clan, Hideyoshi returned from the Tsugoku region within ten days. He quickly absorbed remnants of Oda Nobunaga's army along the way, and met up with Niwa Nagahide and Oda Nobutaka in Sakai. Marching toward Kyoto, he defeated Akechi Mitsuhide at the Battle of Yamazaki, and Akechi Mitsuhide himself was killed while fleeing back to his castle.
Tokugawa Ieyasu with the help of his retainer and ninja leader Hattori Hanzo, at first touring Sakai, fled through several provinces and crossed the mountains of Iga, finally reaching the shore in Ise province. He returned to his home in Mikawa province by sea, and it took him so long that by the time he consolidated his position, Toyotomi Hideyoshi had already had most of Oda Nobunaga's territories under firm control.
Takigawa Kazumasu suddenly faced the assault of the Hojo clan and lost most of his land there, a defeat that cost him much of his previously gained prestige in the Oda clan.
Shibata Katsuie and his forces in the north were bogged down by an Uesugi counterattack in Echizen province, and remained unable to act for quite a while.
The fact that no one else had the chance, resources, or ability to act decisively ensured Toyotomi Hideyoshi's supremacy and spiritual inheritance of Oda Nobunaga's legacy.
In 1587 Toyotomi Hideyoshi built himself a lavish palace in Kyoto. Afterwards, Toyotomi Hideyoshi subjugated Kii province and Etchu province, and invaded Kyushu island and Shikoku island.
He managed the invasions of Kyushu and Shikoku islands in such swift fashion through clever use of diplomacy and a huge invasion force that he had to his disposal. The way he went about this, was accept peace where he could, and reinstate clans to the status of Daimyo, who had prior lost that status, by offering such clans land of clans defeated in the invasions.
One such an example of clans who were confirmed in their holdings, was the Tachibana clan on Kyushu island. The Tachibana clan were an offshoot of the Otomo clan. They were initially led by Tachibana Dosetsu, but he died in 1582 and was without a male heir, instead he transferred power to his daughter Tachibana Ginchiyo, who married Takahashi Muneshige. He had prior been adopted into the clan and had already taken the name Tachibana Muneshige. By not engaging in battle with the invasion force, this clan managed to stay in power. Tachibana Muneshige then fought for Hideyoshi in the Japanese invasions of Korea.
Toyotomi Hideyoshi made peace with the Shimazu clan after a short skirmish following the invasion of Kyushu island.
Next Toyotomi Hideyoshi turned his attention north to the Oshu region, where he forced Date Masamune, nicknamed the "one-eyed dragon" to pledge allegiance to him.
Toyotomi Hideyoshi also made numerous reforms. In 1587, Toyotomi Hideyoshi banished Christian missionaries from Kyushu in an effort to exert greater control over the Kirishitan daimyo. In 1588 Hideyoshi forbade ordinary peasants from owning weapons and started a sword hunt to confiscate arms. The swords were melted down to create a statue of the Buddha. This measure effectively stopped peasant revolts and ensured greater stability.
Now all that remained to be conquered was the territory of the Hojo clan.
He proposed to give these 8 provinces of the Hojo clan to Tokugawa Ieyasu in exchange for the 5 provinces that Tokugawa Ieyasu already held, in order to ensure the support of Tokugawa Ieyasu in the campaign against the Hojo clan. Tokugawa Ieyasu accepted this proposal.
Toyotomi Hideyoshi broke the power of the Hojo clan in the siege of Odawara castle, the stronghold of the Hojo clan. Toyotomi Hideyoshi fielded an army of unprecendented size, it totaled some 220,000 men. There was little actual fighting during the siege, and because Odawara could not be supplied by sea, he basically starved the Hojo into submission. The siege lasted only three months.
By now Toyotomi Hideyoshi was the undisputed ruler of Japan, though he never formally received the title of Shogun due to his peasant background, instead he took the title "Kampaku" or regent.
With the Hojo clan lands conquered, Tokugawa Ieyasu resettled his headquarters into the newly acquired territory as per the agreement, at a place called Edo. Edo was then a small fishing village with a castle that had originally been built by the Ota clan. In next centuries it would become the de facto capital of Japan, and grow into a huge metropolis known by the name of Tokyo.
However troubles were not over yet. In 1591, Toyotomi Hideyoshi's only son, Toyotomi Tsurumatsu died. Hideyoshi named his nephew Toyotomi Hidetsugu as his heir, adopting him in January 1592. Toyotomi Hideyoshi's health now began to falter, but still he yearned for some accomplishment to solidify his legacy, and launched two ill-fated invasions of Korea.
In 1593 a new son was born, named Toyotomi Hideyori, but it seemed certain that the boy would still be an infant by the time his father would ultimately die. And so Toyotomi Hideyoshi decided to appoint five elders to take care of the boy until he would come of age and take over.
Toyotomi Hideyoshi chose his five most powerful daimyo: Ukita Hideie, Maeda Toshiie, Uesugi Kagekatsu, Mori Terumoto, and the famous Tokugawa Ieyasu.
It was Toyotomi Hideyoshi's hope that the five would balance each other, preventing any one of them from taking control. This was not to be.
Toyotomi Hideyoshi finally died in 1598, his infant son was only five years old at that time.
Maeda Toshiie died shortly afterwards in 1599, which left only four of the original five elders alive.
Shortly afterwards the remaining elders divided into two camps, the Tokugawa camp, and everyone else.
Uesugi Kagekatsu was the first to move against Tokugawa Ieyasu, but Tokugawa Ieyasu swiftly defeated him, thanks to the help of Date Masamune. Following his defeat, Uesugi Kagekatsu swore allegiance to Tokugawa Ieyasu.
The two remaining elders, namely Ukita Hideie and Mori Terumoto, now decided to back Ishida Mitsunari, a man, who had previously been a lead bureaucrat in Toyotomi Hideyoshi's government. This political faction would form the western army at the battle of Sekigahara. While Tokugawa Ieyasu and his allies would form the eastern army.
The boy Toyotomi Hideyori was sidelined in all of this, only retaining control of Osaka Castle. He was ultimately attacked and defeated by Tokugawa Ieyasu in the Siege of Osaka and committed seppuku in 1615.
The battle of Sekigahara was won by the eastern army, when Toyotomi Hidetsugu chose to back Tokugawa Ieyasu at Sekigahara, and when a number of key Daimyo in the western army defected.
On March 24, 1603, Tokugawa Ieyasu received the title of "Shogun" from Emperor Go-Yozei marking an end to the Sengoku period, and starting the Edo period. Ieyasu was 60 years old when this happened. He had outlasted all the other great men of his times.