After the reign of Sho Hashi, who united the Ryukyus and established the First Sho Dynasty, the power of the royal court began to taper off. The 7th king to assume the throne in the Ryukyus was Sho Toku who was ambitious in his pursuit of territorial expansion. Without regard to incidents of civil strife and worsening financial conditions from shrine and temple building projects, his reign grew increasingly tyrannical.
After his death by illness, the powerful vassals at court met and recommended that the chief vassal Kanemaru assume the throne. Kanemaru was born in a farming household but his genius was recognized by the 6th heir to the throne King Sho Taikyu and he was appointed to handle foreign diplomacy and finances for the court.
Kanemaru took office using the name Sho En, with the Sho part of his name borrowed from the names of the First Sho Dynasty kings. King Sho En informed the Chinese emperor of the succession and received investiture envoys from China in 1472. His reign began what is called the Second Sho Dynasty which continued unbroken over 19 generations of kings, for 410 years, until the "Disposition of the Ryukyus" edict issued by the Japanese government in the early Meiji era (1868 - 1912).