Seiba ga haru Battle (勢場ヶ原の戦い)
Seiba ga haru no tatakai or Seiba ga haru kassen (Seiba ga haru Battle) was the battle fought between Daimyo (feudal lord) Yoshitaka OUCHI in the Chugoku District (western Honshu) and Daimyo Yoshiaki OTOMO in Bungo Province in May 1534 all over Mt. Omure in Bungo Province (present Yamaura, Yamaga-machi town, Kitsuki City, Oita Prefecture). It was a battle for hegemony over northern Kyushu and the biggest battle between OTOMO and OUCHI.
The battle had various names:
Seiba ga haru no tatakai
Seiba ga haru kassen
Omure san no tatakai (Mt. Omure battle)
Omure kassen (Omure battle)
Omure san no tatakai
Omure san kassen
大牟礼山 and 大村山 (Mt. Omure) read 'Omure san', which was also used as the battle name because the OUCHI army pitched camp there.
From the beginning of the Sengoku period (period of warring states), the Ouchi clan which had been influential in Buzen and Chikuzen in the northern part of Kyushu placed the many regions from Iwami and Aki in the east to Chikuzen, Hizen, Chikugo and so forth in the west under its control. Since the Otomo clan had been shugo (military governor) of Bungo Province for a long time, aiming at subjugation of northern Kyushu, it was infuriated with the Ouchi clan -- There had been small-scale to medium-scale power struggles between the Otomo and the Ouchi clans around such regions as Buzen and Chikugo from the fifteenth century to the first half of the sixteenth century. While fighting the Otomo clan, the Ouchi clan also fought against the Shoni clan and so forth in Chikugo, gradually assuming the hegemony of northern Kyushu.
When father Yoshioki OUCHI died and Yoshitaka OUCHI inherited from his father, Yoshitaka commanded Okifusa SUE, who had taken part in various battles, to conquer northern Kyushu, dispatching him to Kyushu.
In 1533, Okifusa SUE invaded Akizuki, Chikuzen but was defeated by an army commanded by Yoshiaki OTOMO. Here, a battle between the two big cliques seemed to be inevitable.
In 1534, Yoshitaka OUCHI dispatched an army 3000 strong headed by Okifusa, who had returned to Suwa, to Shimonoseki, aiming at subjugation of Bungo where the Otomo clan was based. The Ouchi army advanced, took up a position at Itoguchihara, Usa-gun County, Buzen, and waited to see how the Otomo side would react.
Yoshiaki OTOMO sent an army 2800 strong headed by Ujinao YOSHIHIRO, the castellan of Yoshihiro, Kunisaki, and Mikawa no kami Chikamasa SODA to Mt. Omure, Buzen to oppose the invasion of the Ouchi army to Bungo. In May, the armies, numbering in all 5800 men (6100 men, if the army at Kanagoe-toge pass is included) assembled on the border between Bungo and Buzen, and commenced fighting.
Seiba ga haru Battle
The Otomo camp deployed 1000 horsemen on Mt. Omure, 1000 horsemen headed by Chikazane ICHIMADA and Akinari TAKITA on Tateishi-toge pass between Buzen and Bungo, and 800 horsemen headed by Yasuhisa SHIDE and Masahisa NODA on Jizo-toge pass. Separate from the main armies, 300 horsemen headed by Shigeuji OOGA and Shigeharu HAYASHI encamped at Kanagoe-toge pass.
The Ouchi camp spied out the Otomo camp and embarrassed them, confused the Otomo camp by sending false reports to them -- Then, by taking the advice of Tomoyasu SADA, jito (Steward) in Usa-gun County and the head of the Sada clan, the Ouchi clan went over Sada, and in the early morning on May 28, 1534, went through to the Seiba ga haru field and made a surprise attack on the Otomo camp hidden in Mt. Omure.
The enemy fell from sky!' the Otomo camp was surprised and thrown into panic. Yasunori HIROSE offered an idea that they should call back the armies in garrison on Tateishi-toge pass and Jizo-toge pass in haste and make the horsemen swoop down from the mountain onto the Ouchi army to put them to rout. But Ujinao thought that the enemy was so exhausted that just a small force could defeat them, and said that, above all things, it was sneaky to just look down the enemy moving up the mountain, and rejected the idea. And Ujinao impetuously ran down the mountain, charging the enemy. Unwillingly, the Otomo army followed him. In the beginning, the swooping down Otomo army successfully fought the enemy such that Chikamasa defeated Nagato SUGI in a one-on-one fight -- On the other hand, since the Ouchi army outnumbered the Otomo army, it changed their battle formation to kakuyoku (crane's wing), and encircled and attacked the Otomo army, which resulted in a fierce and desperate battle. Ujinao was at the front and commanded the army, but when an arrow shot his horse, he fell from the horse and fought on foot, then collapsed from an arrow wound. Most of the Otomo army was destroyed in close combat, and those including Chikamasa SODA and Yasunori HIROSE attempted to save Ujinao, but were killed in the battlefield. The Ouchi army raised a shout of triumph, and took a rest.
The armies remaining on Tateishi-toge pass and Jizo-toge pass, numbering 1800 men, launched a counterattack to avenge the battle. From around eleven a.m., the army repeatedly laid an ambush or carried out surprise attacks here and there. Since the mountain was home to most of the soldiers, they played fast and loose with the Ouchi army. The Ouchi army was so intoxicated by successive victories that they could not cope with those surprise attacks and were easily defeated -- That ended up in a thrashing with a great number of soldiers killed and their captain Okifusa SUE wounded. Suffering a reversal, the Ouchi army retreated along the Yorimo-gawa river toward Takada, Bungo and withdrew beyond the sea to Suo.
In the end, the Ouchi army withdrew and the Otomo army won, yet, the battle was a draw in a military sense because the Otomo army also lost its two commanders in chief and the main army was broken up.
Thereafter, the two camps still fought against each other, but in 1538, they finally made peace through the mediation of the twelfth shogun of the Muromachi bakufu, Yoshiharu ASHIKAGA -- As a result, the subjugation of northern Kyushu by Yoshitaka OUCHI met with a hitch. Then, the rise of the Ouchi clan became serious again. Okifusa SUE, who lost in the main battle, was dispatched to Kyushu subsequently to fight the Shoni clan and other powerful clans in Chikuzen, which proved that Yoshitaka still remained trusted.
After the Seiba ga haru battle, there had not been such a big-scale battle between the Otomo clan and the Ouchi clan, and once they made peace, there had not been any clash between the clans. When Yoshitaka OUCHI was killed by Harukata SUE (Dainei-ji no hen (Dainei-ji Temple Incident)), the Otomo clan gained in influence suddenly; conversely, when the Ryuzoji clan, which had once supported the Ouchi clan, became independent, the Ouchi clan lost most of the influence in northern Kyushu -- Accordingly, the Otomo clan assumed the hegemony of northern Kyushu.
Now, 'the battlefield of the Seiba ga haru Battle' remains in Yamaga-machi town, Kitsuki City, and tombstones of those including Ujinao YOSHIHIRO and Chikamasa SODA can be found on the top of Mt. Omure.