Battle of Arita-Nakaide
Date: 10/22 to 10/23 of Eishō 14 (1517)
Location: Arita Castle and its environs in Aki Province
Outcome: The allied forces of the Mōri and Kikkawa overcame an initial long-distance hail of arrows from the Takeda, later killing the opposing leader (Takeda Motoshige) and surrounding the remaining troops at Imada Castle. This marked Mōri Motonari’s first experience and victory in battle.
The Battle of Arita-Nakaide occurred in Aki Province from 10/22 to 10/23 of Eishō 14 (1517). This battle is also referred to as the Battle of Arita. Takeda Motoshige drew upon support from the Amago clan in an effort to restore his position as the former military governor of Aki. The battle commenced with an attack on Arita Castle, home of the Kikkawa clan. This was the first experience in battle for Mōri Motonari.
The arrival of Ōuchi Yoshioki in Kyōto
In 1508, under the influence of the Ōuchi clan of Suō Province, Takeda Motoshige joined Ōuchi Yoshioki in a deployment to Kyōto to install Ashikaga Yoshitane as the shōgun. While the main contingent of the Ōuchi army was in Kyōto, Amago Tsunehisa, the deputy military governor of Izumo Province, stirred conflicts in Aki in an effort to extended his influence in the province. Yoshioki sent Motoshige, the former military governor, back to Aki to confront Tsunehisa. Yoshioki requested Motoshige to fight valiantly, offering for him to wed the daughter of Asukai Masatoshi (the Provisional Chief Councilor of State) whom Yoshioki had earlier adopted.
The expansion of Takeda Motoshige’s influence
In 1515, Motoshige returned to Aki and reclaimed his authority as the military governor of his former domain. He viewed the absence of the main contingent of the Ōuchi clan as a good opportunity to alter the status of Aki as a subordinate province of the Ōuchi. Owing to the origin of his wife from the Asukai clan and their ties to the Ōuchi, he distanced himself from her and received the daughter of Amago Hisayuki (the younger brother of Tsunehisa) as his wife. With the support of the Amago, Motoshige declared himself independent of Ōuchi Yoshioki, and commenced an invasion of the Ōuchi territory. Motoshige seized the landholdings of the Itsukushima Shrine which had witnessed ongoing conflicts, and garnered control of Ōno-Kawachi Castle which had been abandoned by its soldiers. He then attacked Koi Castle, but it did not fall even after a siege lasting for several months. Meanwhile, in order to place in check members of the Yamagata clan (the Mibu, the Arita, and the Imada) allied with the Takeda, Yoshioki ordered Mōri Okimoto and Kikkawa Mototsune to deploy to Arita in the Yamagata District. The toppling of Arita Castle enabled Motoshige to end the siege of Koi Castle and to aim his forces to the north, commencing attacks against numerous castles allied with the Ōuchi in the Yamagata District.
After Mōri Okimoto died in the eighth month of 1516, a two-year-old child named Mōri Kōmatsumaru became his successor as head of the clan. His uncle, Mōri Motonari, served as his guardian, but, at the time, Motonari himself was only twenty years old. The clan became visibly unstable, presenting Motoshige with an opportunity. The youthfulness of Motonari along with the limited forces of the Mōri and Kikkawa clans appeared to be no match for the authority of the Takeda as the prior military governors of Aki under Motoshige who had been compared to an infamous Chinese warrior for his bravery. Their lord, the Ōuchi, had deployed the bulk of their forces to the capital of Kyōto so there was no prospect of receiving reinforcements.
The course of events
In the second month of 1517, Motoshige advanced toward Imada Castle in the Yamagata District and called for allegiance in an effort to rally influential families to his cause. Local families opportunistically gathered, totaling over 5,000 troops led by Kumagai Motonao (lord of Miiri-Takamatsu Castle), Kagawa Yukikage (lord of Yagi Castle), and Koi Sōzui (lord of Koi Castle). In the autumn, Motoshige encircled Arita Castle, defended by Oda Nobutada under the command of the Mōri and the Kikkawa, both which were allied with the Ōuchi clan. The castle defenders numbered about 300 men. Nobutada appealed for surrender, but Motoshige rejected him.
On 10/21, the Takeda army (comprised of 600 mounted soldiers from the Kumagai, the Yamanaka, and the Itagaki) attacked and set fire to dwellings in Tajihi to provoke the Mōri. Motonari quickly responded by rounding-up 150 mounted soldiers from Sarugake Castle in Tajihi to repel the Takeda army. Once Motonari finalized his strategy, he called for reinforcements from Yoshida-Kōriyama Castle. A total of 700 mounted soldiers from the main branch of the Mōri clan led by his younger brother, Aiō Mototsuna, along with Katsura Motozumi, Watanabe Suguru, Fukubara Sadatoshi, and members of the Inoue clan, the Saka clan, the Kuchiba clan, the Akagawa clan, the Awaya clan, and the Kodama clan converged with reinforcements totaling 300 mounted soldiers led by Miya-no-shō Tsunemoto from the Kikkawa clan to confront the Takeda army.
On 10/22, the allied forces of the Mōri and Kikkawa marched to Arita to confront 500 mounted soldiers led by Kumagai Motonao fighting on behalf of the Takeda. The allied forces first endured a long-distance hail of arrows from the Takeda army. Then, fearing a pincer attack, at once flung themselves at the Kumagai forces to engage in hand-to-hand combat. Motonao dismissed the opposing forces owing to their limited numbers and made a frontal assault. At the height of the battle, Motonao went to the front lines to yell at the soldiers. Unfortunately for Motonao, an arrow pierced his head, causing him to fall from his horse, whereupon Miya-no-shō Tsunetomo took his head. As a result, the Kumagai forces lost their will to fight and fled in disarray.
Upon hearing this news, Motoshige responded by ordering Tomo Shigekiyo and Shinagawa Nobusada to lead 700 forces to encircle Arita Castle, while he led the main contingent to attack the allied forces of the Mōri and Kikkawa. The Takeda forces were arrayed in a V-shape or crane-wing formation with five rows on a side. The allied forces advanced to the Matauchi River. Meanwhile, the Oda forces burst out of Arita Castle only to retreat in the face of attacks by a large number of Takeda soldiers, after which members of the Oda began to flee. Urgent shouts of encouragement from Mōri Motonari finally convinced the men to halt their escape, and, gradually, the front line began to move ahead. The grinding situation prompted Motoshige to mount a horse and go to the front line, crossing the Matauchi River. At that moment, the Mōri forces shot arrows in unison at the Takeda forces attempting to cross the river. After being struck by an arrow, Motoshige fell and died on the bank of the Matauchi River. Inoue Mitsumasa from the Mōri army launched the fatal shot. Having lost their leader, the Takeda army collapsed and retreated to Imada Castle.
Among the surviving troops gathered at Imada Castle, Tomo Shigekiyo, Shinagawa Nobusada, and Awaya Shigemune argued in favor of retreating and waiting for an opportunity to counterattack, while Kagawa Yukikage and Koi Sōzui insisted upon re-engaging the enemy to avenge their losses. The next day, Yukikage and Sōzui led forces out of the castle to attack the Mōri army and realized a heroic end in battle.
Later, this battle was likened to the Battle of Okehazama in which Oda Nobunaga defeated the large army of Imagawa Yoshimoto of Suruga in a surprise attack, wherein this battle was referred to as the Okehazama of the Western Provinces. This battle further marked the decline of the Aki-Takeda clan and a watershed moment in the rise of the Mōri clan. A significant loss of leadership including Takeda Motoshige, Kumagai Motonao, and Kagawa Yukikage led to rapid decline in the military capabilities of the Aki-Takeda clan, which were finally extinguished by the Mōri family. Motonari quickly gained notoriety for killing Motoshige, the former military governor of Aki, in his first experience in battle. In a letter of condolences written by Ōuchi Yoshioki while residing in Kyōto, he praised Motonari as marvelous. Thereafter, Motonari succeeded Kōmatsumaru as head of the clan after Kōmatsumaru’s premature death.