Penghu Xiyu Battery Group (Xiyu East Fort & West Fort)

The Penghu Xiyu Battery Group (澎湖西嶼砲台群) comprises two major Qing Dynasty coastal fortifications — Xiyu West Fort (西嶼西臺, commonly known as 西台古堡 "West Fort Ancient Castle") and Xiyu East Fort (西嶼東臺) — located on Xiyu (西嶼, also called Fisherman Island/漁翁島) in the Penghu Archipelago, Taiwan. Together they formed a critical component of the Taiwan Strait defense network, commanding the approaches to Penghu's inner harbor alongside Jinguitou Fortress (金龜頭砲臺) and Dacheng North Battery (大城北砲臺).

ORIGINS AND QING DYNASTY CONSTRUCTION

Xiyu had hosted military installations since the late Ming-Zheng period. In 1683, when Qing admiral Shi Lang launched his assault on Penghu, Ming loyalist general Liu Guoxuan had already constructed battery positions on the island. These early fortifications underwent periodic rebuilding during the Kangxi reign (1662–1722).

The catalyst for the modern fortress complex was the Sino-French War (1884–1885). In March 1885, French Admiral Courbet's fleet attacked Penghu and briefly occupied the islands, exposing catastrophic weaknesses in the archipelago's defenses. After the war's conclusion, Taiwan Governor Liu Mingchuan personally inspected Penghu's military situation and submitted multiple memorials to the Qing court urging comprehensive fortification of the Taiwan Strait approaches.

The court approved Liu's plan and appointed Wu Hongluo (吳宏洛) as the first Penghu garrison commander (澎湖總兵). With assistance from a German engineer recorded in Chinese sources as 鮑恩士, four modern batteries were designed and constructed simultaneously: Xiyu West Fort, Xiyu East Fort, Jinguitou Fortress, and Dacheng North Battery. Construction began in 1886–1887 (sources differ on the year) and was completed in 1889 (Guangxu 15th year).

XIYU WEST FORT (西嶼西臺 / 西台古堡)

Located on the southern coast of Wai'an Village (外垵村), Xiyu West Fort is the crown jewel of Penghu's military heritage. Covering 8.15 hectares, the entire fortress is ingeniously concealed within the natural basalt cliff formations — invisible from the sea. The design features a distinctive "mountain" character (山字型) layout with three parallel tunnels connected by cross-passages. The main tunnels are 13 chi (approximately 4 meters) wide and 11 chi (approximately 3.5 meters) tall, with walls 2 chi (approximately 0.6 meters) thick, capable of housing a garrison of 54 soldiers.

The fort was armed with four Armstrong breech-loading cannons of varying caliber: one 6-inch gun, two 10-inch guns, and one 12-inch gun — representing the most advanced Western artillery technology available at the time. The ammunition magazines, gun emplacements, and barracks were all integrated into the underground tunnel system, providing excellent protection against naval bombardment.

Above the main entrance, a stone tablet reads 西嶼西臺. Who wrote it is disputed: studies of the fort attribute the calligraphy to Liu Mingchuan, while Taiwan's Tourism Administration credits Li Hongzhang (李鴻章), the powerful Qing statesman who oversaw much of China's late-19th-century military modernization; the tablet itself carries only a date (third month of Guangxu 13, 1887). This inscription remains intact today.

XIYU EAST FORT (西嶼東臺)

Located at the southeastern tip of Nei'an Village (內垵村) at a promontory known locally as Xiaojiaojiao (East Cape), Xiyu East Fort covers approximately 1.3 hectares. It is roughly rectangular in plan with its gun positions facing the sea, enclosed by two ramparts and an exterior trench for defense. The fort mounted three gun emplacements equipped with 7-inch, 8-inch, and 10-inch Armstrong breech-loading guns.

Working in concert with Xiyu West Fort to the southwest, the East Fort controlled Penghu's inner bay approaches and the southwestern sea lanes. Together the paired fortifications created overlapping fields of fire that could deny enemy vessels access to the harbor.

JAPANESE COLONIAL PERIOD (1895–1945)

When Japan launched its invasion of Taiwan in 1895, Penghu was the first territory seized — Japanese forces came ashore at Longmen on March 23, 1895, even before the main Taiwan campaign began. The strategic value of Penghu's fine natural harbor for the Imperial Japanese Navy was immediately recognized: the islands gave Japan's coal-burning warships an advanced base to control the Taiwan Strait and prevent Chinese reinforcements from reaching Taiwan.

In 1896, the Japanese military established the Penghu Island Fortress Artillery Battalion (澎湖島要塞砲兵大隊) and formulated the Penghu Island Fortress Battery Renovation Plan (澎湖島要塞砲台修建計畫), which expanded artillery installations and increased garrison strength across all existing Qing-era batteries including both Xiyu forts. The batteries were integrated into the broader Japanese coastal defense network that stretched from the Home Islands through Okinawa to Taiwan.

During the Pacific War, Makō (馬公, modern Magong) served as a major Imperial Japanese Navy base and was the embarkation point for the invasion of the Philippines. Penghu's strategic position made it a key node in Japan's southern defense perimeter. However, because the United States adopted an island-hopping strategy that bypassed Taiwan and Penghu after securing the Philippines — leaping directly to Okinawa — the Penghu batteries never engaged in direct combat with American naval forces. The 1944 Penghu air raids caused damage across the archipelago, but the absence of a ground or naval battle meant that many of Penghu's fortifications, including the Xiyu batteries, survived the war remarkably intact.

POST-WAR AND PRESERVATION

After Japan's surrender in August 1945, the Republic of China assumed control of Penghu. The Xiyu batteries were no longer maintained as active military installations. Xiyu West Fort was designated a First-Class National Historic Monument (一級古蹟) on December 28, 1983 — one of the first 15 sites in the inaugural batch of national monument designations. After legislative amendments in 1997, it was reclassified as a National Historic Monument (國定古蹟). Xiyu East Fort received its national monument designation on November 23, 1991.

Today, Xiyu West Fort is one of Penghu's premier tourist attractions. Visitors can explore the extensive tunnel network, view the replica Armstrong cannons on display, and see the inscribed tablet above the gate. Admission to the fort is ticketed. Xiyu East Fort is freely accessible and retains its gun emplacements and defensive earthworks. Both sites offer panoramic views of the Taiwan Strait and serve as powerful reminders of the strategic importance of the Penghu Archipelago across centuries of East Asian military history.