The circle indicates the time we are discussing in this section.
After Jokyu-no-Ran (11|Jokyu-no-ran ), the power of the Imperial court declined significantly. The Hojo clan who were the main power during the Kamakura period began to have the financial difficulty and started to lose the control over the local lords. One of the reasons was that the cost incurred by the Mongolian invasion. The Kamakura Bakufu (government) could not reward the local lords who worked hard at this war. The local lords became very dissatisfied with the Kamakura Bakufu. Seeing this as a chance, the Emperor Go-Daigo twice attempted to attack Kamakura Bakufu but failed both times and he was exiled to Oki island. Meantime, Ashikaga Takauji (足利尊氏) and several other groups of Samurai who were opposing the Kamakura Bakufu, gathered their power and succeeded in destroying the Kamakura Bakufu (1333). This ends the Kamakura period. The Emperor Go-Daigo, who had been exiled to Oki island returned to Kyoto and attempted established political reforms. This is called Kenmu-no-Chuko (建武の中興). This new policy failed to satisfy the most of the ruling class. Taking advantage of this situation, Ashikaga Takauji attacked Imperial court in Kyoto, deposed the Emperor Go-Daigo and placed the other branch of the Royal family on the imperial throne. But the Emperor Go-Daigo insisted upon his legitimacy, moved to Yoshino (located the South of Kyoto) and established a rival Imperial court. Thus began the North and the South dynasty. Much strife between the North and the South and also, both side had their own problems within themselves. Eventually more Samurai group went under the control of North dynasty. About 60 years later, Southern dynasty was compelled and accepted the Ashikaga clan’s proposal. Thus, established the North Dynasty as the legitimate imperial court. This 60 years is the time called Nanboku-Cho or Yoshino-Cho period. During Nanboku-Cho period, Samurai demanded larger and showy, and practical swords. Soshu Den was its height of their prominence. That does not mean only Soshu group made all the swords. Other schools and other provinces also made Soshu Den style swords.
Early Soshu den time (that is late Kamakura period), Yukimitu (行光), Masamune (正宗) and Sadamune (貞宗) were representative swordsmiths. Middle Soshu den time (that is North and South dynasty time), Hiromitu (広光), Akihiro (秋広) were representative swordsmiths. Late Soshu den time (that is Muromachi period), Hiromasa (広正), Masahiro (正広) was the representative swordsmiths.