The Battle of a Nation, and the Rise of a New Shogun

“Sekigahara Battle Screen” | Artist’s depiction of the battle from the north | 19th century | Courtesy of Wikimedia Commons

The Battle of Sekigahara took place in Japan near the end of the Sengoku Jidai or The Warring States Period (1467-1615). These nearly 150 years were the most violent times in Japanese history, where warlords battled each other for land and power. Since this period lasted for so long, the way battles were fought had changed. The first battle of the Sengoku Jidai that happened in 1467, called the Onin War, was fought with bows and swords, but by the end of the era, battles were influenced by the introduction of European cannons and guns. The Onin War, which started it all, had lasted for ten years and was instigated by the Hosokawa and Yamana clans. At that time, the capital of Japan was Kyoto, which housed the Ashikaga Shogunate, and it was the Ashikaga that held authority over the country. In the city, both clans owned mansions and their rivalry took a turn for the worse. The two clans fought in the city, and others who were caught in the crossfire had to choose to side with one or the other to protect themselves. Soon the situation spiraled out of control and the shogunate was not able to quell the fighting. The Onin War caused a domino effect that started with the Hosokawa and Yamana clans, and year by year the whole country was at war.1

During the Sengoku Jidai, there were three great unifiers, the first being Oda Nobunaga, who conquered central Japan. He started making waves in 1560, when a powerful warlord attempted to take over Nobunaga’s territory. Severely outnumbered by the invading Imagawa clan, Nobunaga managed to take Imagawa Yoshimoto by surprise under the cover of a thunderstorm and killed him. This victory marked the beginning of Nobunaga’s conquest of central Japan and was now aided by fair weather clans who had supported Imagawa. Eight years later, in 1568, with the help of his ally Tokugawa Ieyasu, who was watching his back, Nobunaga started his march towards Kyoto to remove the shogun and put himself in power. Needless to say, this aggressive move was not well received by the other warlords, who felt threatened by Nobunaga taking control of Kyoto. Doubly so by Ieyasu moving from his castle in Okazaki to another more advantageously positioned Hamamatsu castle in 1570. The location of Hamamatsu castle was at the mouth of the Tenryugawa river, which starts in the territory owned by Nobunaga’s rival Takeda Shingen. The Takeda clan was another prominent force that should not be taken lightly. Takeda Shingen marched in the snow towards Hamamatsu castle and had forced Ieyasu’s forces back behind the walls. After the defeat, Ieyasu’s general Torii Mototada had ordered the gates to be closed. Ieyasu knew that that was what Shingen wanted, so he told Mototada to leave them open and light fires to guide the retreating troops back. Surprised by this, Shingen thought that the gates being left open was a trap, so he decided not to storm the castle and had his troops camp out in the cold. Making use of the terrain, Ieyasu had sent out 16 riflemen and 100 other foot soldiers at night to attack their camp. The Takeda were known for their horsemen, but in this case it was their downfall when the Tokugawa troops led the horsemen down to a ravine. Under the cover of darkness coupled with the snow, many of the horsemen could not stop in time and fell in, while the Tokugawa soldiers finished them off.2

“Map of Japan in provinces in time of Iyeyasu” | Map of Japan that shows the provinces during the Tokugawa shogunate and a smaller map showing the Sekigahara campaign | 1903 | Courtesy of Wikimedia Commons

Since Nobunaga’s conquest of Kyoto, things had been going well and he had become the most powerful man in Japan. In the summer of 1582, Nobunaga’s general Toyotomi Hideyoshi fought against the Mori clan on the west side of the country, while Tokugawa Ieyasu was fighting on the east side. Hideyoshi’s battle at Mori’s Takamatsu castle stagnated, and he was unable to break through the Mori defenses. In order to win, he decided to request reinforcements from Nobunaga. What Hideyoshi didn’t know was that his request came with a major consequence. Nobunaga had sent out his troops in advance under the command of another general by the name of Akechi Mitsuhide and he would catch up to them at Takamatsu castle. This had left Nobunaga unguarded, and at night Mitsuhide turned the army around with the intention of betraying Nobunaga. During the attack, Nobunaga was staying at Honnoji temple in Kyoto when Mitsuhide’s troops arrived and set the temple ablaze, knowing that he could not escape, Nobunaga took his own life and died in the fire.3

After the event, Mitsuhide declared himself the Shogun, and after hearing the news, Hideyoshi surrendered his assault and took his troops back to Kyoto. Surprised that Hideyoshi returned so quickly, Mitsuhide was caught off guard and had his troops position themselves on a hill by the Yodo river; but it was for naught. Hideyoshi had routed the enemy who had dispersed in all directions, and Mitsuhide died at the hands of a peasant gang.4 But Hideyoshi’s work was far from over; he could not be the shogun because he was not from a notable family; so he became the civil prime minister. Hideyoshi picked up where Nobunaga left off and became the second great unifier. And by 1591, he had control of the entire country. Seven years later, in 1598, Hideyoshi became ill and his heir was only five years old. Before he died, Hideyoshi held a meeting with five of the strongest warlords and made them swear to rule together along with five commissioners until his son was of age to take his father’s spot. The five warlords were Tokugawa Ieyasu, Maeda Toshiie, Uesugi Kagekatsu, Mori Terumoto, and Ukita Hideie. Hideyoshi had made Toshiie the guardian of his son along with Tokugawa Ieyasu. Then on September 15, 1598, Hideyoshi had succumbed to his illness.5

This was where the scheming and working in the shadows took place, because everyone knew that the country was not going to remain peaceful, now that Hideyoshi was dead. The first to start the scheming was Ishida Mitsunari, who was trying to decrease Tokugawa Ieyasu’s influence. After Ieyasu moved into the late Hideyoshi’s castle, Mitsunari went to Toshiie, who was the guardian of Hideyoshi’s son, to try and turn him against Ieyasu. Luckily for Ieyasu, Hosokawa Tadaoki was there to counteract Mitsunari’s scheming and convinced Toshiie and his son that it would be in his best interest to not mess with Ieyasu. Having his plan backfire, Mitsunari then chose to stage an assassination of Ieyasu, but that too failed when Ieyasu’s generals found out about it. They had decided to kill Mitsunari, and in a surprising turn of events, Mitsunari fled for his life and sought protection from Ieyasu. No one knows why Ieyasu granted Mitsunari protection, but his choice made the future tougher for himself.6

“The First Shogun of the Tokugawa Shogunate” | Woodblock print of Tokugawa Ieyasu | 1836-1880 | Yoshitora Utagawa | Courtesy of Wikimedia Commons

So, who was this Tokugawa Ieyasu? He held territory in the “breadbasket” of Japan, which made him a very wealthy and powerful man. Power was determined by how much food-bearing land someone controlled, and Ieyasu’s territory in the Kanto region provided him with 2.5 million koku. One koku is 180 liters of rice, which is enough to feed a man for one year. Coupled with being rich, Ieyasu had chosen strong allies; he was on Nobunaga’s side, while other clans perished while trying to oppose him; and he was smart enough to back Hideyoshi’s rule. After Maeda Toshiie died, Ieyasu became the guardian of Hideyoshi’s son Hideyori, and he moved into the Osaka castle where Hideyoshi was staying. This angered the commissioners and warlords, including Mitsunari. But during that time Ieyasu also dealt with the troublesome Uesugi clan that was to the east of Japan. Mitsunari saw this opportunity, and himself and a group of others issued a complaint that Ieyasu believed was a declaration of war.7

Since the time of Hideyoshi’s death, everyone was forming alliances, and Ieyasu was no different. A rule that he broke being one of the rulers was that he could not marry off children for diplomatic reasons. But that was one of the ways he had formed alliances that allowed him to form the Eastern Army. The Eastern Army, led by Tokugawa Ieyasu, were the separatists who did not want to wait for Hideyori’s son to rule. When the Eastern Army formed, Mitsunari then formed the Western Army, who were the loyalists. The whole country was now divided by whom they supported. Ieyasu had started the campaign in the east and split his army; he sent his son to attack the Sanda clan, while he led 30,000 men towards the west where Mitsunari was. Getting closer, Ieyasu ordered his subordinates to take Gifu and Kiyosu castles, which were on two important roads, while Mitsunari was taking Fushimi castle, whose defenses were strong and held up his army. After taking Fushimi castle, he moved on to Ogaki castle, where he met with the Eastern Army and had a skirmish in Akasaka. Nothing came out of it, but at night a couple of Mitsunari’s generals had posed a night battle and believed they had the upper hand. Mitsunari’s strategist scoffed at the idea, calling it weak, and Mitsunari called for a retreat to a more strategic location at a village in a valley called Sekigahara.8

The year was 1600, and both armies had arrived at around 1:00 am, but a torrential rain was coming down and by the time both had set up their positions, it was 4:30 am. Mitsunari’s plan was to draw the Eastern forces into the valley and surround them; two sides of the valley were blocked my mountains, which made running away difficult. The rain had let up and had turned into a dense fog. By 8:00 am, the fog had lifted and both armies were surprised by how close they were to one another. Both armies had around 80,000 troops, and the Eastern Army kicked off the battle with mounted cavalry led by Ii Naomasa and Fukushima Masanori straight to Ukita Hideie’s positon. The push had shocked the Western Army, and 20,000 more Eastern forces charged towards Mitsunari’s encampment. Mitsunari then had cannons fire upon the west to be used as a fear tactic, which succeeded, and forced his enemies back. Two hours had passed and only 35,000 of Mitsunari’s alliance had joined the battle. The Shimazu clan, 3000 in total, had not moved from their position. Angered by this, Mitsunari personally went to their camp and asked them to join the battle. Shimazu did not respond positively, which may have been because his advice about the night attack prior to the battle had been scoffed at.9

Map based on the Battle of Sekigahara | 09-07-2008 | Created by Rage Against | Legend translation: Yellow: turncoats Blue: West army Red: East army | Courtesy of Wikimedia Commons

Another hour passed and the battle went back and forth with no clear winning side. Mitsunari, looking from a vantage point at Mount Sasao, had called for all of his forces to make a final push. Mitsunari had an ace up his sleeve; 15,000 men led by Kobayakawa Hideaki had been waiting on Mount Matsuo for Mitsunari’s call to charge at the Eastern Army. But before the battle, Hideaki had sent a letter to Ieyasu that told him that he would switch sides to the east. When Mitsunari signaled for Hideaki, he did not respond. At the same time, four other divisions and Kikawa Hiorie were ordered to attack, but they too defied Mitsunari’s orders. Hideaki having been given a push by Ieyasu and charged towards Mitsunari’s forces, and the Shimazu clan then fled from the fight. Overwhelmed, the remaining Western Army had lost and Mitsunari was captured and executed in Kyoto.10  Tokugawa Ieyasu was now the third great unifier, which led the country to 200 years of peace. His descendants had feared that foreign influence would thrust the country back into another age of war, so they turned away all foreigners, with only a few exceptions for trade.11

  1. Stephen R. Turnbull, War in Japan 1467-1615, Essential Histories 46 (Oxford: Osprey Publishing, 2002), 8-14.
  2. Stephen R. Turnbull, War in Japan 1467-1615 Essential Histories 46 (Oxford: Osprey Publishing, 2002), 42-49.
  3. Stephen R. Turnbull, War in Japan 1467-1615 Essential Histories 46 (Oxford: Osprey Publishing, 2002), 52-53.
  4. Stephen R. Turnbull, War in Japan 1467-1615 Essential Histories 46 (Oxford: Osprey Publishing, 2002), 54.
  5. Anthony J. Bryant, Sekigahara 1600: The Final Struggle for Power, Osprey Military Campaign Series 40 (London: Osprey, 1995), 7-8.
  6. Anthony J. Bryant, Sekigahara 1600: The Final Struggle for Power Osprey Military Campaign Series 40 (London: Osprey, 1995), 9, 10, 12.
  7. Anthony J. Bryant, Sekigahara 1600: The Final Struggle for Power Osprey Military Campaign Series 40 (London: Osprey, 1995), 8,12,13,14.
  8. Anthony J. Bryant, Sekigahara 1600: The Final Struggle for Power Osprey Military Campaign Series 40 (London: Osprey, 1995), 12,13,38,39,41,49.
  9. Anthony J. Bryant, Sekigahara 1600: The Final Struggle for Power. Osprey Military Campaign Series 40 (London: Osprey, 1995), 25,51-65.
  10. Anthony J. Bryant, Sekigahara 1600: The Final Struggle for Power Osprey Military Campaign Series 40 (London: Osprey, 1995), 47,66-80.
  11. Stephen R. Turnbull, War in Japan 1467-1615 Essential Histories 46 (Oxford: Osprey Publishing, 2002.), 87.

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34 Responses

  1. Thank you Raul for this article! I know very little about Japanese history but this article helped informed me a lot about the history and politics of Japan. This article was very information heavy however easy to follow and an interesting read. Japan’s history is great when examining the development of a nation and what is needed to develop. Nations in transition need a stable and united military/government to prosper and develop as a whole.

  2. I found this article interesting from beginning to end and the authors style of writing made it super easy to just keep being engaged. I find it interesting just how there was a constant fight among the generals for power. It seems that it is human nature to seek power when it is available which is a bit scary if you think about it. I also found it interesting how everyone began forming alliances after the death of hideyoshi’s death. This was a great article as it is fascinating the see the lengths that leaders will go to to obtain power in their nation.

  3. Hi Raul! I really enjoyed this article and the structure throughout made it easy to follow along. The fight and struggle for power amongst the generals is what caught my eye the most. The fighting and hunger for more power is what both captivated me, and scared me at the same time. It is overwhelming to think about the lengths leaders will go to in order to obtain control. This hunger is an important component to focus on, especially when thinking about how leadership and governance of a nation comes to be. The unification component is often even more important and gives a nation and people some hope for the future after violence and conflict. Great article

  4. The aspect of this article which I found most pertinent was the ending. Don’t get me wrong, the entire article was action-packed and gloriously told! But with the Tokugawa shogunate’s closing off of the nation, it set in motion the status quo which would exist in Japan from the 1600s all the way until Commodore Matthew Perry came with his black-sailed ships in the 1800s. — arguably thrusting Japan headlong into its record modernization; its involvement in global conflict such as the Sino-Japanese War and World War II; and its economic and technological boon time.

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