- Type: Okinawan gusuku
- Built: 14th century
- Status: Ruins
- Other Names: 島添大里城 (Shimasoe Ôzato gusuku)
- Japanese/Okinawan: 大里城 (Oozato gusuku / Ufuzato gushiku, Ufuzato gusuku)
Ôzato gusuku (O: Ufuzato gusuku), is traditionally said to have been the seat of power of the kingdom of Nanzan, which controlled southern Okinawa in the 14th-15th centuries. While recent scholarship has challenged the notion of distinct territorial states in this period, Ôzato was certainly one of the most powerful and important centers of power in southern Okinawa, controlling some of the best freshwater springs and arable land on the island. Also known as Shimasoe Ôzato gusuku, it is not to be confused with Shimajiri Ôzato gusuku, also known as Nanzan gusuku.
According to the Chûzan seikan, Ôzato gusuku was first built in the 14th century by Ufuzato anji, King of Nanzan. Located about 180 meters above sea level on a cliff in Ôzato village in the town of Nishibaru, it was protected by the cliff on the north and west sides, and by tall stone walls.
The castle grounds cover roughly 20,000 square meters, making Ôzato one of the five largest gusuku on the island. The enclosures range from east to west, and the first (highest & central-most) enclosure is surrounded to the north, but left open to the south and east. Little remains of the walls, which were used as construction materials elsewhere in later centuries. The grounds also include a well, called Chichin-ga, located at the bottom of an eight-meter (43 steps) stone staircase, which was built when the castle's natural spring, known as Sukuyamanu-ga, dried up.
The Lord of Ôzato sent tribute to Ming China on eight occasions under the title of "king of Nanzan," and received letters and goods in return. Ultimately, however, it would be the lord of Urasoe/Shuri (i.e. the "Chûzan king") and not Ôzato who would be recognized by China as the sole true authority in the Ryukyus. Nanzan is also mentioned in the Omoro sôshi as being widely renowned, and a site of great treasure, which has drink (saké) in abundance.
Ôzato fell to Shô Hashi, king of Chûzan, around 1429. Having already conquered the north of Okinawa a decade earlier, in seizing Ôzato, Hashi united the entire island under his rule, marking the establishment of the Kingdom of Ryûkyû.
- Kitahara Shûichi. A Journey to the Ryukyu Gusuku 琉球城紀行。 Naha: Miura Creative, 2003. pp63, 71.
- Gregory Smits, Maritime Ryukyu, University of Hawaii Press (2019), 97-97.
- According to some accounts, Hashi conquered the south first. Smits, Maritime Ryukyu, 77-78.