The political entity was identified as a tiny country,[2][3][4] a kingdom, or a principality by modern historians, however the ruler of Hokuzan was in fact not "kings" at all, but petty lords with their own retainers owing their direct service, and their own estates.

Okinawa, previously controlled by a number of local chieftains or lords, loosely bound by a paramount chieftain or king of the entire island, split into these three more solidly defined kingdoms within a few years after 1314; the Sanzan period thus began, and would end roughly one hundred years later, when Chūzan's King Shō Hashi[note 1] conquered Hokuzan in 1416 and Nanzan in 1429.

In addition to its deficiencies in agriculture and fishing, Hokuzan suffered from the disadvantage, relative to Chūzan, of holding no port to equal Naha (O. Naafa).

Chūzan entered a tributary relationship with Ming dynasty China in 1372, and Hokuzan and Nanzan were granted similar commercial status shortly afterwards.

After the annexation of Sanhoku, Shō Hashi, king of Chūzan, appointed his second son Shō Chū the "Warden of Nakijin Castle, Sanhoku" (山北今帰仁城監守, commonly known as "Warden of Hokuzan" 北山監守) in 1422, a post which would remain for many years, holding little overall power, but serving to maintain order in the north on behalf of the Chūzan court at Shuri.

At the end of the 17th century, Sanhoku nominally comprised 9 magiri (間切): Onna, Kin, Kushi, Nago, Haneji, Motobu, Nakijin, Ōgimi, and Kunigami.