Battle of Yōkamachi
Date: Tenth month of Tenshō 10 (1582)
Location: The village of Yōkamachi in the Araki township of the Araki District of Hida Province
Outcome: Seeking to take advantage of turmoil after the demise of Oda Nobunaga, Ema Terumori launched a nighttime attack against Mitsuki Yoritsuna (an ally of the Oda), but was pursued and killed the following day, enabling the Mitsuki to take control of most of Hida.
The Battle of Yōkamachi occurred in the tenth month of Tenshō 10 (1582). The battle unfolded in the village of Yōkamachi in the Araki township of the Araki District of Hida Province and was waged between Mitsuki Yoritsuna and Ema Terumori who had divided power within the province. Owing to its historical significance, it is also referred to as the Sekigahara of Hida.
After the Honnō Temple Incident on 6/2 of Tenshō 10 (1582), a coup d’état that resulted in the unexpected death of Oda Nobunaga, the power of the Oda clan collapsed. In the tenth month of 1582, Terumori, the head of the Ema clan based in the Takahara township, took advantage of the turmoil to advance his army into the townships of Araki, Furukawa, and Kojima. Terumori had committed to a final showdown for control of Hida against Mitsuki (Anekōji) Yoritsuna, the provincial governor of Hida who maintained close ties to the Oda.
Course of events
According to an account written in the Edo period, the Mitsuki fielded 1,000 soldiers while the Ema army had 300 mounted soldiers. Based on other sources that are contemporaneous with the time of the event, at around 2:00 AM on 10/26 of Tenshō 10 (1582), the Ema forces launched a nighttime attack against an ally of the Mitsuki named Kojima Tokimitsu at Kojima Castle. However, those in the castle fought back ferociously so the Ema forces retreated to Araki. The next day, Mitsuki Yoritsuna, along with Kojima Tokimitsu, Ushimaru Chikamasa, and Hirose Munekuni, attacked the Ema forces at Yōkamachi and Terumori was killed in action.
On the day after the Battle at Yōkamachi, Tokimitsu attacked as far as Takahara and toppled the base of the Ema clan at Takahara-Suwa Castle. This event extinguished the Ema clan. Later, except for the Uchigashima clan who governed the Shirakawa township, there was no one remaining to oppose the power of the Mitsuki clan within Hida so that the Mitsuki (later known as the Anekōji) clan pacified nearly all of the province.