The Story of the Japanese 01433 [Sanzan] Summary of the Sanzan Period

We have looked at the period from the myths of Okinawa to the unification of the Ryukyu Kingdom in the 4th year of Xuande (1429). However, the basis for this article is the official history of the Ryukyu Kingdom, such as:
・Chuzan Seikan: Established in 1650
・Chuzan Sufu: Completed in 1701
・Kyuyo: Completed in 1745 (with subsequent additions)
Therefore, this is merely a history that is convenient for the dynasty.
In historical records, the progression has been: "Tenson Dynasty → Shuten Dynasty → Eiso Dynasty → Sanzan Period (Satto Dynasty, Haniji Dynasty, Ozato Dynasty) → Unification of Ryukyu by Sho Hashi." But where exactly does the legend end and historical fact begin?
Many historians seem to view the existence of dynasties up to the Eiso Dynasty as questionable. This is because the description that "the unified Ryukyu split into three countries because the fourth king of the Eiso Dynasty, Tamagusuku, neglected governance" is highly likely to have been created to justify Sho Hashi's unification of Ryukyu. The truth is likely the opposite: it is thought that the many Aji (local lords) who were crowded together gradually unified and converged into three countries.
In Japan as well, the Book of Han Geography states that in the 1st century, Japan was divided into over a hundred countries fighting each other, which by the 3rd century had become the large framework of the Yamatai confederation, and by the 5th century had grown into the Yamato Court, which resonated even in Kanto and Kyushu. Historians believe that Ryukyu must have followed a path similar to other countries in the world.
The history after the Satto Dynasty contains legendary episodes and moral evaluations that are dubious, but if we look at it based on facts such as "when, who fought whom, and who destroyed whom," the general outline seems to be historical fact.
However, since it is a history book compiled by officials of the Ryukyu Kingdom, which was under strong influence from the Ming Dynasty, there may be some degree of biased evaluation or misidentification of facts. For example, regarding the timing of the fall of the Hokuzan Kingdom, even within the "Chuzan Sufu," there are discrepancies:
・In the edition compiled by Shitahaku Tensho (1646–1725), it is the 20th year of Yongle (1422).
・In the edition compiled by Sai On (1682–1762), it is the 14th year of Yongle (1416).
This discrepancy is thought to have arisen because the Hokuzan Kingdom last paid tribute to the Ming in the 14th year of Yongle (1416), and Sai On thought, "If the country still existed, they would have paid tribute every year." In reality, although the Hokuzan Kingdom continued to exist until the 20th year of Yongle (1422), they likely stopped paying tribute to the Ming midway through.
Now, although Ryukyu was unified, internal strife occurred again after the death of Sho Hashi, and the First Sho Dynasty ended surprisingly quickly. I would like to summarize that part of the history in the next chapter.