Xiyu Ammunition Depot (Penghu)

The Xiyu Ammunition Depot (西嶼彈藥本庫, also known as 漁翁島彈藥本庫 or Fisherman Island Ammunition Depot) is a military storage complex located on the western side of Dongbitou Mountain and the southern side of Niuxin Mountain in Nei'an Village, Xiyu Township, Penghu County, Taiwan. It is one of the best-preserved Japanese colonial-era ammunition storage facilities in Taiwan.

Following Japan's seizure of the Penghu Islands in March 1895, the Imperial Japanese military established the Penghu Island Fortress (澎湖島要塞). Under the "Penghu Island Fortress Defense Directive" (澎湖島要塞防禦要領書), construction of twelve artillery fortifications began in 1900. Five major ammunition repositories were planned across the archipelago, including this facility at Xiyu, which was completed in Meiji 35 (1902). The depot served as the primary ammunition supply point for the western Penghu defense sector.

The complex comprises three distinct structures: two underground dry ammunition storage chambers and one above-ground cooling ammunition bunker. The underground cavern-style magazines feature a double-walled barrel-vault construction — concrete blocks form the external shell while reinforced concrete lines the interior, creating an air gap that regulates temperature and humidity for storing sensitive smokeless powder. The magazines are connected by a 23-meter lateral passage and adopt both H-shaped dual-chamber and linear single-chamber floor plans. Notably, the inner walls are lined with copper sheeting to provide electromagnetic shielding and moisture isolation, an advanced technique for the era.

The above-ground cooling magazine (清涼彈藥庫) features stone outer walls with wooden interior walls and moisture-resistant elevated wooden flooring. Its roof employs a complex steel frame supporting dark-baked Japanese ceramic tiles with lightning protection. This experimental structure blends Western military engineering with local materials and represents an important example of late Meiji-era fortification architecture.

After Japan's surrender in August 1945, the Republic of China military inherited the facility and renamed it the Niuxinwan (Ox Heart Bay) Ammunition Depot (牛心灣彈藥集積所). The site remained under military control until 2010, when the Penghu County Government designated it a county-level historic site. Following extensive restoration work from 2010 to 2021, the depot opened to the public on April 13, 2021, as the Xiyu Ammunition Depot Military Culture Park (西嶼彈藥本庫軍事文化園區). On August 2, 2024, it was elevated to national historic site status, recognizing its exceptional architectural and historical value.