The Bessho were a samurai clan during Japan's Sengoku Period, based at Miki Castle in Harima province. The Bessho were originally a cadet branch of the Akamatsu clan, a powerful shugo daimyo clan in direct service to the Ashikaga shoguns during the Muromachi Era. By the end of the Sengoku Period, the Akamatsu had greatly declined in power, whereas the Bessho had gained in strength.
When the powerful general Hashiba Hideyoshi entered Harima in 1576 on the orders of Oda Nobunaga, the Bessho originally surrendered on the orders of the main branch of the Akamatsu clan, but when Hideyoshi advanced to engage with the mighty Mōri clan to the west, the Bessho rose in rebellion. Allegedly the Bessho elders, as descendants of the illustrious Minamoto clan, couldn't bear the thought of having surrendered to Hideyoshi, who had been born a commoner.
In any case, Hideyoshi was forced to break off his campaign against the Mōri to resolve the rebellion at his rear, razing the Bessho's border castles one by one and finally laying siege to Miki Castle itself in 1578. The Bessho, under the command of their daimyo, Bessho Nagaharu, managed to hold out for nearly three years, an extraordinarily lengthy period of time for a beseiged castle to hold out.
The Bessho's survival was in part due to secret resupply missions by the Mōri navy. However, these supply lines were eventually discovered and eliminated, and although the Bessho held on for nearly a year after that, eventually they ran out of food and surrendered, in 1580. Bessho Nagaharu was compelled to commit suicide in order to vouchsafe the lives of the remaining defenders inside Miki Castle, and the Bessho clan's 200-year history as an independent warrior house came to an end.