It had roots in the late army of Chūzan, which became the Ryukyu Kingdom under the leadership of King Shō Hashi.

Ryukyu primarily fought with other Ryukyuan kingdoms and chiefdoms, but also Japanese samurai from Satsuma Domain and pirates.

On 11 March 1422,[note 2] Shō Hashi gathered the forces of the ajis of Urasoe, Goeku, and Yomitanzan at Shuri.

Shō Hashi allowed Gosamaru, Yomitanzan Aji, to build Zakimi Castle for supporting him in the war.

[11] Uni-Ufugusuku was awarded Goeku Magiri (越来間切, modern Okinawa City) and built Chibana Castle.

This included the development of the hiki (引) system, which had been the basic military unit since Shō Hashi.

Shō Shin turned them into a quick reaction force with military, police, and administrative duties.

[2] He confiscated weapons from the peasantry, then forced the aji to relocate to his capital to minimize the chances of rebellion and to centralize the military under total royal control.

[2] Also in 1522, Shō Shin had the Pearl Road (真珠道, madama-michi) constructed between Naha and Shuri to allow quicker troop movement between the port and the royal palace, which was then extended by his son, Shō Sei, to connect Tomigusuku, Mie, and Yarazamori Castle in 1546.

[14] After Satsuma landed on Kouri Island, across from Unten Harbor, Ryukyu sent a thousand soldiers, commanded by Nago Ryōhō, to reinforce Nakijin Castle.

[15] On 30 April, Nago Ryōhō's force met the Satsuma army near Nakijin, but retreated after sustaining a 50% casualty rate; Nakijin was captured and razed and Shō Kokushi, the garrison commander and the heir to the Ryukyuan throne, died from wounds sustained in the battle.

[20] While the hiki system was reduced in status during the 17th century, Ryukyu's military remained to defend the country and its tribute ships from pirates in the East China Sea.

Ryukyuan ships were defended by soldiers and armed with cannons; fleets of nearly 100 junks were used during some of Ryukyu's military campaigns.

[2] Common myths state that karate developed because of confiscations of or bans on weapons by King Shō Shin and Satsuma Domain, respectively.