Soma Shigetane was the 6th head of the Soma clan. In 1323, he led his clan from Nagareyama in Shimosa Province (present-day Chiba) down to Namekata district in Mutsu Province, initially residing at Bessho Hall in Ota (present-day Odaka Ward, Minamisoma). In 1326 he moved his base to Odaka Castle, founding what would become known as the Oshu Soma line. In 1336 he ordered his second son Mitsutane to renovate Odaka Castle. Thereafter, Odaka Castle served as the Soma clan's seat for approximately 280 years, until the clan moved its base to Ushigoe and then Nakamura Castle in 1611.

A pioneering clan head who accomplished the major undertaking of relocating his clan from Shimosa to Mutsu and establishing a new base in unfamiliar territory.

Shigetane's entry into Odaka Castle marked the founding moment of the Oshu Soma clan, which went on to rule the Soma region (the northern Hamadori area of present-day Fukushima) for roughly 700 years. The Odaka Castle site, also known as "Kobaisan Ukifune-jo," is now a Fukushima Prefecture Historic Site.