Sakamoto Castle was constructed by Akechi Mitsuhide on the orders of Oda Nobunaga. This famous castle fell ten years later alongside Mitsuhide when he lost the Battle of Yamazaki after the Honno-ji Incident.
Afterwards, Nobunaga’s chief vassals assembled at Owari Province’s Kiyosu Castle and divided his domain. Niwa Nagahide controlled Omi in Shiga and Takashima and became lord of Sakamoto Castle, while Hashiba Hideyoshi (Toyotomi Hideyoshi) gained Yamazaki Castle. Many voices supported Hideyoshi to be the lord of Sakamoto Castle at the meeting, but it was passed over to Niwa Nagahide because it was thought that Hideyoshi would have the ambition of ruling the whole country if he obtained the castle. This is because Sakamoto Castle was a favorable and important location for transportation to Kyoto.
However, Hideyoshi breached Shibata Katsuie’s defenses at Kitanosho Castle in Echizen Provinze in April of 1583, and Ietsugu Sugihara obtained Sakamoto Castle after Nagahide was awarded Echizen, Wakasa, and the Kaga Peninsula. The rumors of Ietsugu’s madness nevertheless actually resulted in Asano Nagayoshi, who had been awarded Seta Castle, receiving Sakamoto Castle at the meeting at Kiyosu Castle. Otsu’s importance then rose and Otsu Castle was given a historical role as Sakamoto Castle’s role of watching over Enryakuji Temple’s Mountain Order. Additionally, Hideyoshi built Osaka Castle to link Osaka and the Hokuriku Region by land and water routes through the Tokaido Road and Yodo River.
Later, Sakamoto Castles ruins were converted into crop fields and residential housing districts after it was abandoned. What once was a famous castle has now become a ghost of its former self, with its past scope and location being unclear.
However, it has been said since the Edo period that the castle was located near a temple called Tonan-ji. In fact, slightly north of Tonan-ji Temple is the Akechi Mound, which is said to be the grave of the Akechi clan and is still carefully enshrined today. Also, when the water level of Lake Biwa drops, the stone walls of Sakamoto Castle remaining in the lake appear, occasionally offering a glimpse of what it looked like in the past.