Hachigata Castle was a mountain castle built in Musashi Province (now Saitama Prefecture) in 1476 by Nagao Kageharu in defiance of the Yamanouchi-Uesugi Clan which his clan served when the then-clan head Uesugi Akisada passed him over for inheritance of the position of Nagao clan head in favor of his younger brother Nagao Tadakage.
Five years later, Oota Doukan of the Ougigayatsu branch attacked the castle and finally took the castle for Uesugi Akisada. During the next few decades the two branches of the Uesugi Clan fought over the castle.
After the Battle of Kawagoe Castle in 1546, the Houjou Clan became the rulers of Musashi, and Houjou Ujikuni became master of the castle in 1564. Thereafter it served as one of the bases from which the Houjou Clan controlled the Kantou.
It strategic position at an important crossroads made it a target for various attacking warlords, including Takeda Shingen in 1569 and Uesugi Kenshin in 1574, but its formidable defenses, both natural (nestled as it is between two rivers and high cliffs) and man-made, enabled it to repel all comers.
The castle withstood siege from 35,000 troops with a garrison of only 3,000 for a month during the Siege of Odawara, but Ujikuni finally surrendered on the condition that the lives of his men would be spared.