目次～Table of Contents
Location and History
Introduction
The battle of Sekigahara, which occurred on the 15th of September 1600 (according to the lunar calendar), is one of the biggest events in Japanese history. The highlight of the battle has been said to be the betrayal of Hideaki Kobayakawa. The widely accepted theory says the followings. Hideaki first supported the western allies and settled on Matsuoyama Castle, in the south of the Sekigahara field. However, he still waited to see the battle for a while, wondering which ally would be better, the eastern or the western. He had made a secret agreement with Ieyasu Tokugawa, who was the top of the eastern allies, to support. Initially, Koyakawa did not move, therefore Ieyasu got tired of waiting. He then ordered his soldiers to shoot at the Hideaki’s troops. The shooting was called “Toi-deppo” which means to force by guns. Hideaki was very surprised to hear that. In that instance, he quickly decided to support the eastern allies. This indecision by Kobayakawa lead to the death of Mitsunari, but gave victory to Ieyasu.
Recent studies suggest the betrayal of Hideaki and the Toi-deppo story.
The whole story of the Sekigahara battle is consisted of very few primary sources and many other secondary sources. The Toi-deppo story comes from one of the secondary sources. The Sekigahara Battle is long. One part of the story refers to Toi-Deppo, which was first written in the Keicho Gunki, a war chronicle which was written over 50 years after the battle. If the story is a fiction, the timing of Hideaki’s decision would also be doubtful. Historians are trying to re-create the Sekigahara story by reviewing the few remaining primary sources and some of the secondary ones which were reliable. In addition, Matsuoyama Castle has been said to be the base of Hideaki Kobayakawa during the Sekigahara battle. However, it would also be important to know when and how the castle was built and used.
This article will explain three different theories of Hideaki and Matsuoyama Castle with three different viewpoints.
The viewpoints will include:
a. What and where did Hideaki go before the Sekigahara battle?
b. Why did Sekigahara become the battlefield and when and how did Hideaki settle on Matsuoyama Castle?
c. When did Hideaki really decided to support the eastern allies?
The theories on this article will include:
- The defacto theory including the Toi-deppo story
- The theory that Hideaki was not a betrayer
- The theory that the western allies would attack Matsuoyama Castle
As a preface, I will describe the prehistory of Hideaki and Matsuoyama Castle before the battle.
Hideaki and Matsuoyama Castle before Sekigahara Battle.
Hideaki was born in 1582 as the fifth boy of Iesada Kinoshita who was the big brother of Kitano-mandokoro, the first lady of Hideyoshi Toyotomi. He was adopted by Hideyoshi when he was a child and was raised by Kitano-mandokoro. Surprisingly, Hiedaki celebrated his Coming of Age at only 7 years old and became a noble. This was because he was one of the candidates to be Hideyoshi’s successor. However, after Hideyori Toyotomi, Hideyoshi’s own child was born, Hideaki was adopted again by the Kobayakawa Clan. Hideyoshi thought Hideyori would have become his successor.
There is an interesting episode about that from a war chronicle as follow. Hideyoshi originally wanted to adopt Hideaki to the Mori Clan and for the Mori Clan to take over, which was the head family of the Kobayakawa Clan. Takakage Kobayakawa, the lord of the clan offered Hideyoshi to accept Hideaki to protect his master. However, according to historians, Takakage probably decided it by himself. This was because Takakage was an independent lord after he was given his own territory by Hideyoshi. Takakage might have thought he would return his territory to Hideyoshi’s relative to maintain the good relationship with Hidesyoshi.
Hideaki’s new territory was at Chikuzen Province (which is part of Fukuoka Prefecture) which was one of the basements for the invasion of Koria by Hideyoshi. Hideaki also went to Korea as the supreme commander when he was 16 years old (so, it was just a formality). However, when he went back to Japan in 1598, he was moved to Echizen Province (the current Fukui Pref.) by Hideyoshi. The reason for it is uncertain. War cornicles suggest that Hideaki made a mistake in the invasion, while historians speculate that Hideyoshi wanted to rule Chikuzen Province directly to boost his invasion. The fast is, after Hideyoshi died, that Hideaki returned to Chikuzen Province and considered one of the great lords of Japan, following the members of Counsil of Five Elders in the top government. The battle of Sekigahara would happen then.
Matsuoyama Castle was located on the border between Omi (the current Shiga Pref.) and Mino (Gifu Pref.) Provinces. A record says that a retainer of Nagamasa Azai, who owned Omi Province, was assigned in the castle. This was probably because Nagamasa was against Nobunaga Oda who owned Mino Province at that time. Nobunaga eventually had gotten Omi Province before the castle was abandoned. On 10th of Argust, 1600 (according to the luna calendar), Mitsunari Ishida entered Ogaki Castle. Mitsunari ordered his retainer to resume Matsuoyama Castle. Mitsunari thought that his Western Allies would attack the Eastern Allies based on Ogaki Castle, backed up by other mountain castles. Matsuoyama Castle was one of them. A historian speculates that Mitsunari thought that Terumoto Mori, the greatest lord in the Western Allies would enter Matsuoyama Castle. Anyway, the castle was developed again to prepare for the battle.
The defacto theory including the Toi-deppo story
It is confirmed that the Western Allies captured Fushimi Castle on 1st of August (according to the luna calendar). It is also certain that the troops of Hideaki Kobayakawa joined the attackers as the main force. After that, according to the de facto theory, many of the Western Allies, including Mitsunari Ishida, stayed in Ogaki Castle, while Hideaki marched over Omi Province (the current Shiga Province). Evidence of his action there remains at a temple of the province. It is a noticeboard to Hideaki’s soldiers to ask them not to do violence in the temple.
Hideaki still supported the Western Allies, however, he also negotiated with the Eastern Allies. A secret letter from Nagamasa Kuroda and Yoshinaga Asano to Hideaki before the battle says as followings.
“We (Nagamasa and Yoshinaga) will need to serve Kitano-mandokoro.
You need to decide to support us until Ieyasu would come.”
Nagamasa was taken care of by Kitano-mandokoro earlier on. He persuaded Hideaki that it would be needed to support the Eastern Allies if Hideaki wanted to serve Kitano-mandokoro from then on.
Ieyasu arrived at Aakasaka Camp on the 14th of September, near Ogaki Castle. He wanted to have a field battle, he was good at, so he needed to lure Mitsunari out from the castle. Ieyasu intentionally announced that he would attack Sawayama Castle, which was Mitsunari’s home and far to the west from Ogaki. Mitsunari was surprised to hear that, left the castle, got ahead of Ieyasu, and took up positions on Sekigahara Field on the way to Sawayama. Hideaki also reached Matsuoyama Castle in the south of Sekigahara in accordance with Mitsunari’s instructions. Historians speculate that Mitsunari might have tried to withdraw to Sawayama Castle with his own decision. This is because a letter of Hiroie Kikkawa, who was one of the members of the Western Allies on Nangusan Castle between Ogaki and Sekigawara, says so. However, Mitsunari couldn’t do so but had to prevent the Eastern Allies from invasion at Sekigahara on the way. Yoshitsuku Otani, a lord of the Western Allies only expected that Hideaki would betray, so Yoshitsugu’s troops moved closer to Matsuoyama.
The battle between the Eastern and the Western Allies occurred early in the morning on the 15th. It went back and forth until noon. Hiroie’s troops on Nangusan and Kobayakawa’s troops didn’t move because of their secret agreements with Ieyasu. However, Ieyasu got annoyed as Hideaki had also promised that he would join the Eastern Allies. That’s why Ieyasu ordered the Toi-deppo. Hideaki’s decision was around the noon. Some of the soldiers who joined the Western Allies testified after the battle as followings.
The Eastern Allies and Otani’s troops battled each other 6 or 7 times in the morning. Kobayakawa’s troops, then, rushed down from the mountain into Otani’s side and destroyed them.
As for the Toi-deppo story, it may be a fiction as mentioned above. However, a historian found another tradition that might have been the origin of the story as following.
An old man in Bizen Province (the current Okayama Pref.) heard about an interesting story from the Kobayakawa’s retainer. During the battle, Hideaki heard about gunshots at the foot of the mountain. His retainers reported that the shooters of the Eastern Allies said it was just a misfire. The retainers also added it might have included something else.
The historian speculates that the shooting could have been an indirect reminder from Ieyasu. This tradition is still one of the second sources.
The theory that Hideaki was not a betrayer
I will next explain a new theory about Hideaki and Matsuoyama Castle. Accorting to this theory, it is uncertain where Hideaki was after the battle of Fushimi Castle before the Sekigahara Battle. The de facto theory says he was in Omi Province at that time. However, that comes from the family records of Inaba Clan which was written during the Edo Period. The records also say their founder, who was a senior vassal of Hideaki, captured Matsuoyama Castle for the Eastern Allies. That means the records were edited by his descendants to stress the contributions to the current shogunate, which may not be reliable now. On the other hand, a lord of the Eastern Allies reported that Hideaki stayed in Ogaki Castle just before the Sekigahara Battle. That’s contradictory. Overall, Hideaki seemed to still be wondering which ally would be better while acting with the Western Allies.
In addition, there is also no certain evidence where Hideaki was at the beginning of Sekigahara Battle. However, another evidence suggests it. The letter of Hiroie Kikkawa, mentionabaned above, says an interesting matters.
In addition, there is also no certain evidence where Hideaki was at the beginning of Sekigahara Battle. However, another evidence suggests it. The letter of Hiroie Kikkawa, mentioned above, says an interesting matters.
“The Western Allies moved from Ogaki Castle to Yamanaka (the west of Sekigahara) to rescue Yoshitsugu Otani because Hedeaki would be against them just before the battle.”
According to the letter, Hideaki and Yoshitsugu had already been around Sekigahara.
