Grierson Reef

Grierson Reef ; Sin Cowe East Island ; Mandarin, is a cay on the eastern part of the Union Banks of the Spratly Islands in the South China Sea. The island has been occupied by Vietnam since 1978. It is also claimed by China (PRC), the Philippines, Vietnam, and Taiwan (ROC).

Geography

The original island was approximately 160 meters long, 60 meters wide, and surrounded by a sandy shore ranging from 5 to 10 meters in width. The natural land area of the island was approximately 1.6 hectares. Both ends of the island feature sandbars that shift seasonally with wind and wave patterns.
In 2014, Vietnam constructed a seawall around the island and expanded it, adding approximately 1.2 hectares of land, bringing the total area of the island to approximately 2.8 hectares. From 2019 onwards major defensive structures were built on the island, such as bunkers, coastal fortifications, and possibly missile pads.
On June 7, 2022, the Vietnam Buddhist Sangha inaugurated the Sinh Tồn Đông Pagoda on the island.
Starting in March 2025, Vietnam began land reclamation activities to expand Sinh Tồn Đông Island while dredging a harbor on the southern part of the island.