The Siege of Odawara
In 1590, the third Siege of Odawara took place. Meanwhile, the Hojo clan is the last strong resistance against the flourishing leadership of Toyotomi Hideyoshi. He is known to be Oda Nobunaga’s successor in ruling over Japan. The Odawara Castle, the biggest castle in the world then was the homeland of the strongest Daimyo in Japan, the Hojo clan. This is the very reason why this was the central target of the siege of Toyotomi.
Hojo clan was able to come up with a plan to defend their castle and preserve their power of resistance against Hideyoshi, their rival. That is by utilizing the help of his ally castles in the Kanto area through guerrilla attacks. But Hideyoshi, backed up with the biggest army of Japan, sure has the upper hand.
The Long-Standing Dispute: Hojo Vs. Sanada Clan
Hōjō Ujinao governs the Hojo clan during this time. He was one of the Daimyo of the late Sengoku period and the fifth head of Hojo clan. Before his assumption as head, he was a strong supporter of the Takeda clan. Even after the death of Takeda Katsuyori, he still didn’t transfer his loyalty to the powerful Oda Nobunaga and Tokugawa Ieyasu tandem.
He even defeated Oda’s general Takigawa Kazumasu together with his father, Ujimasa in the Battle of Kanagawa. He also followed up with a series of conquest on Oda territories.
The Tokugawa agreed on a truce with Ujinao during their dispute on the provinces of Shinano and Kai. He gave the Kai province to the Hojo clan. Another interesting fact was in the year 1584, Ujinao marries Tokugawa Ieyasu’s daughter Matsudaira Tokuhime.
On the other hand, the Sanada Clan was led by Sanada Masayuki, also a Daimyo in the Shinano province. He was previously a Takeda clan vassal in the province of Kai. He was popular as a strong leader and one of the greatest military strategists having defeated the powerful Tokugawa army in the Siege of Ueda. He was also believed as most feared by Tokugawa Ieyasu. He eventually became a vassal to Toyotomi Hideyoshi.
He became an independent Daimyo under Toyotomi regime because of his powerful political prowess.
In 1589, Toyotomi Hideyoshi fixed the conflict between these two, the Hojo and Sanada clan regarding their claims on the Numata castle and the Azuma Valley in the area of Kozuke province. Toyotomi gave most of the disputed land to the Hojo clan and only giving Sanada clan some territory in the southern Shinano, specifically the Azuma district and the north of Numata, the Nagurumi castle.
The Dishonor on the Agreement Made
Even if the territory claims have been mediated by Toyotomi already, a Hojo retainer named, Inomata Kuninori, was not happy about it. Kuninori attacks the Nagurumi castle, in the west of the Tone River, defended by the Sanada troops. The siege was successful and the Hojo troops were able to seize the castle.
Prior to this attack, Toyotomi Hideyoshi had already made a law prohibiting all the Daimyo from engaging into battle schemes to solve private conflicts. That is why this incident is obvious disobedience of this rule, leading the battle in Odawara castle.
How the Siege Unraveled
The Hojo clan thought that Toyotomi will not push through with his siege due to logistical difficulties going to their impressive stronghold, Odawara. With this being said, this battle is one of the most unconventional Samurai battles in Japan’s history.
Toyotomi made a stone wall castle in a mountain top opposite Odawara castle to be their siege camp. There was not much fighting during this siege, it consists mostly of food and supplies starvation tactics.
This pushed for the rise of merchants, mostly bringing in supplies for Hideyoshi troops for a great profit.
It was unusual for Hideyoshi troops not attacking the castle despite its enemies are outnumbered. The reason for his discouragement was that this castle had survived previous attacks already.
On the other side, the Hojo troops defending the Odawara castle just slept on their walls with their battle armories and arquebuses. Their food supplies were cut and the support from their ally castles surrounding them was blocked.
Few battles erupted between the two sides. One distinct was when a group of miners from Hideyoshi troops residing in Kai dug a broad tunnel under the walls of the outer walls of Odawara castle. It allows the Samurai under the lead of Ii Naomasa from Hideyoshi troops to enter Odawara castle in covert with the use of Shinobijutsu (castle entering techniques).
The siege lasted for three months. The Hojo clan surrendered when seeing that they are outnumbered and struggled so much from food and supplies shortage. Besides Odawara castle, Hideyoshi was also able to defeat Hojo clan territories namely Hachiōji, Yorii, and Shizuoka; as well as the southwestern part of the bulk of Hojo clan land, Kantō region.
The Siege Concluded
This successful siege in favor of Toyotomi Hideyoshi made him fully eliminate the last opposition for his rise in ultimate power all over Japan. This victory of him and rise to power signified the conclusion of the Sengoku period. This was also the time when Toyotomi Hideyoshi got an agreement with Tokugawa Ieyasu. He offered Ieyasu the eight provinces in the Kantō region previously ruled by the Hojo clan. In exchange, Ieyasu agreed on giving up his governing five provinces namely Mikawa, Tōtōmi, Suruga, Shinano, and Kai to Toyotomi.
A tea master named, Yamanoue Sōji was sentenced to death in a morbid way. He was known to be a loyal servant of the Odawara lords, the Hojo clan then.
After this battle has concluded, Toyotomi Hideyoshi restored the control of Numata including the Nagurumi castle to the Sanada clan.
This has always been the flourishing time of Toyotomi Hideyoshi, as he conquered the whole country of Japan.
The Effect of this Siege in Modern Times
Samurai Warriors 2 adapted the Siege of Odawara in their gameplay. In the Sengoku Basara Season 2 anime, it features Odawara Castle as the place where the fight took place between Date Masamune and Toyotomi Hideyoshi. In the fight, Hideyoshi died in the castle, under the hands of Masamune. After that, Ishida Mitsunari went inside the castle and saw Hideyoshi died. He then lamented gravely.
Lastly, nowadays, Toyotomi Hideyoshi’s popular siege camp is still existing and is popularly known as the Ishigaki “stone walls” mountain. It is the so-called made up castle during this siege, built opposite the Odawara castle.