It is said that his parents died when he was around twenty and undertook to provide for his aunt and uncle, brother and sister, and his wife, whom he married at a very young age.

[5] Leaving Ginama, he traveled to Shuri, the capital of the Ryukyu Kingdom, in 1441, and became a servant or retainer to the prince, Shō Taikyū.

After Shō Taikyū became king in 1454, Kanamaru was made royal treasurer,[5] and was in 1459[4] granted the post of Omonogusuku osasu no soba (御物城御鎖側), a position involving responsibility for matters regarding foreign relations and trade.

[4] Historian George H. Kerr, however, points out that official histories produced in the following centuries were written with the patronage of Shō En's successors; also that the circumstances surrounding Shō Toku's death remain something of a mystery, and the traditional account may simply indicate that there was a shift in allegiances among the aristocrats and bureaucrats towards Kanamaru, or that those parties in support of Kanamaru simply outnumbered those on the side of the late king.

Shō En's childhood wife is believed to have died, or otherwise separated from Kanamaru, before he rose to prominence at Shuri.