The Ryukyu Kingdom was a long-standing one, continuing for 450 years from 1429 until 1879. The Ryukyu Dynasty is split into the First Sho Dynasty, relating to Sho Hashi, who unified Ryukyu, and the Second Sho Dynasty, which was in political power from 1470 onwards. Sho En came to the throne as the founder of the Second Sho Dynasty.
Sho En was born in 1415 in Shomi, on Izena Island, the son of farmers. In his youth he was apparently known as Nishi-no-Machigani. As a child, he was a hard worker, farming and growing rice. Then, one year, the island experienced a drought. While rice fields all over the island dried out, only Sho En's fields remained full of water. One theory says that the unmarried women of the island, enamored of Sho En's good looks and diligence, carried water to his fields every night.

However, other youths on the island, jealous in any case of Sho En's popularity, unanimously blamed him, and denounced him as a thief, claiming that the reason his fields did not dry up was because he was stealing water from the fields of others. Sho En protested his innocence to the island's administrator, but his protests fell on deaf ears. Instead, the island youths planned to murder him, using the theft of the water as a pretext.
Sensing his life was in danger, Sho En lost hope in the island where he had been born and raised, and made the decision to leave the island, "like the giant Dapeng bird, which flies for 10,000 miles when it spreads its wings." He boarded a boat with his wife and younger brother, who was still a young child (who later became Sho Sen'i, second king of the Second Sho Dynasty), and left the island. He was 24 at the time.

Having left the island, Sho En lived for a brief time in Kunigami, in the northern part of Okinawa's main island, but after three years he moved to Shuri, where he became a servant of Prince Goeku, who was the younger brother of Sho Kinpuku, the fifth king of the First Sho Dynasty of the Ryukyu Kingdom. Originally possessed of a sharp mind, the diligent Sho En's talents were soon recognized, and Prince Goeku strongly recommended him to King Sho Kinpuku. Thus, in 1447, Sho En was to begin his life as a low-ranking government official called a Geraeakukabe. Here Sho En displayed his abilities and distinguished himself even further, succeeding to the extent he was able wear the yellow headband that indicated the status of a high-ranking official.
Here Sho En displayed his abilities and distinguished himself even further, succeeding to the extent he was able wear the yellow headband that indicated the status of a high-ranking official. Then, in 1454, when Prince Goeku became King Sho Taikyu, 6th of his line, Sho En was given even more responsibility, being appointed Lord of Nishihara in that same year.

Five years later, at the age of 45, he assumed the role of Omonogusuku Usasu no Soba, a position involving responsibility for matters regarding finance and foreign relations. A post on the Council of Three, which would be the equivalent of a government minister today, was now right before his eyes, but his fate would change with the death of King Sho Taikyu.
The seventh king, Sho Toku, was a tyrant. Grief and sadness spread all over the country. Unable to just watch, Sho En offered his counsel, but his advice went unheeded. Sho En resigned his post, and confined himself to his territory of Uchima.
After the death of Sho Toku, there was a coup d'état by retainers in the royal government, during which Sho Toku's successor was killed. The retainers nominated Sho En to be the next king. Adamantly refusing at first, he was later convinced, and eventually became king.