Otsu-jo Castle (大津城)
Otsu-jo Castle was located in Otsu, Shiga County, Omi Province in the Azuchi-Momoyama period.
Otsu-jo Castle, a "hira-jiro" (castle built on level ground) lay on the area around present-day JR West Otsu Station in Hamaotsu, Otsu City, Shiga Prefecture, and the "honmaru" (keep and main areas) of the castle was located near the existing pier in Otsu Port of Lake Biwa. In the Battle of Sekigahara, a few of the fierce battles were fought over Otsu-jo Castle as well as Ueda-jo Castle or other castles. It is said that the noise of the battle reached as far as Kyoto everyday and some citizens went to see the battle with lunch bags and water bottles.
Otsu-jo Castle was abandoned after the war, and some parts of the castle including the keep were reportedly transferred to Zeze-jo Castle or Hikone-jo Castle. When the keep of Hikone-jo Castle was disjointed and repaired in 1957, some notes and inscriptions in India ink were found, which indicates the possibility that the keep of Hikone-jo Castle was built from the materials once used in the keep of Otsu-jo Castle. Based on the finding, the keep of Otsu-jo Castle is thought to have been a "boro" (lookout tower) type of keep, and to have looked like a four-story building from the outside, but actually had five floors on the inside.
In 1586, Hideyoshi TOYOTOMI abandoned Sakamoto-jo Castle and ordered Nagamasa ASAI to build another castle, Otsu-jo Castle. Later, the ownership of the castle was transferred from the Masuda clan to the Shinjo clan and, in 1595, it was given to Takatsugu KYOGOKU with a stipend of 60,000 koku (approximately 10.8 million liters of crop yield).
In the Battle of Sekigahara in 1600, Takatsugu belonged to East squad and barricaded himself in Otsu-jo Castle. However Otsu-jo Castle was not suitable for battles, because the castle was originally used for safely preserving materials transported from Mino Province or Echizen Province by the waters of Lake Biwa. The castle was surrounded by the 15,000 soldiers of the West squad including Motoyasu MORI and Muneshige TACHIBANA in October 13, 1600, which was the beginning of the battle over the castle. Before the battle, the 3000 soldiers of the Kyogoku Army burned away the castle town for 12 hours until the town changed into a barren field. Kyogoku Army including AKAO Izu no kami (Governor of Izu Province) and Oi YAMADA fought to defend the castle for seven days, but, on October 19, they were attacked with cannons from nearby Mt. Nagara and the cannonballs rained down on the keep and other buildings of the castle, destroying them. The Tachibana Army occupied the second keep of the castle taking advantage of the confusion inside the castle. Finally, a peace treaty was approved through the mediation of both Kozosu, a close aide of Kodaiin, and Mokujiki Ogo, a monk from Mt. Koya. On October 20, Takatsugu surrendered the castle, and then he went to Onjo-ji Temple to become a monk and went up to Mt. Koya. However, since Takatsugu's service of riveting the 15,000 solders of the West squad to Otsu-jo Castle was notable, Ieyasu TOKUGAWA sent for him after the war and gave him Wakasa Province as his territory with the ownership of Obama-jo Castle and the increased stipend of 82,000 koku (approximately 14.8 million liters of crop).
Shortly after Takatsugu moved to Wakasa Province, Ieyasu abandoned Otsu-jo Castle and built a new castle, Zeze-jo Castle in Zezezaki. Some parts of Otsu-jo Castle which escaped damage in the battle over the castle were transferred to Hikone-jo Castle and Zeze-jo Castle.