Former Imperial Japanese Army Meteorological Department

The Imperial Japanese Army Meteorological Department (陸軍気象部) was established on April 11, 1938, under Imperial Ordinance No. 240, as a specialized military agency tasked with "conducting research, investigations, and statistics related to military meteorology, as well as research, testing, inspection, and assessment of meteorological instruments, and education in the academic disciplines necessary for meteorological service." The department operated under the direct command of the Chief of the General Staff, with its director holding the rank of major general.

The department's origins trace back to 1935, when a meteorological section was first created within the Army Artillery Engineering School. As Japan's military operations expanded across East Asia and the Pacific, the need for a dedicated, independent meteorological organization became apparent. The 1938 ordinance formalized this by establishing the department at Mabashi 4-chome in Suginami Ward, Tokyo (present-day Koenji-kita 4-chome). In 1941, reflecting its growing importance, it was renamed the Army Central Meteorological Department (陸軍中央気象部).

During the Pacific War, the department's role was critical to military planning, especially for aerial operations, naval coordination, and strategic missions. Weather intelligence determined the timing of air strikes, supply operations, and troop movements across the vast Pacific theater. The department maintained an extensive network of meteorological observation stations and field offices throughout Japan proper, Korea, Manchuria, China, and the occupied territories of Southeast Asia. Its personnel staffed weather stations equipped with military communication facilities, providing real-time data to operational commanders. Notably, the department's research contributed to unconventional warfare projects, including the Fu-Go balloon bomb campaign (風船爆弾), which relied on precise knowledge of the jet stream to carry incendiary devices across the Pacific to North America.

In April 1944 (April 10, according to the shrine's history), a Shinto shrine dedicated to weather — the Kishō Shrine (気象神社), whose annual festival falls on June 1, Meteorological Day — was built within the department's compound, enshrining the deity Yagokoromoikane no Mikoto (八意思兼命), associated with wisdom and deliberation. The shrine reflected the spiritual dimension of the wartime meteorological mission, providing a place of prayer for forecasters committed to accurate predictions that could determine the outcome of military operations. The shrine burned down in the American air raid of April 13, 1945, and was rebuilt before the war ended.

Following Japan's surrender in August 1945, the Army Meteorological Department was dissolved along with the rest of the Imperial Japanese military. Its personnel, expertise, and functions were absorbed into the civilian Central Meteorological Observatory (中央気象台), specifically its research division, which eventually became the Meteorological Research Institute (気象研究所) of the Japan Meteorological Agency in 1956. The institute occupied the former military site until relocating to Tsukuba Science City in 1980. The vacated land was subsequently developed into Mabashi Park (馬橋公園), which opened in 1985 as a public green space in the densely populated Suginami neighborhood.

Today, Mabashi Park bears little visible trace of its military past. However, the Kishō Shrine survived in an unexpected way: despite the GHQ Shinto Directive of December 1945, which ordered the removal of militaristic shrines, the weather shrine was overlooked during inspections and escaped destruction. In 1948, it was relocated to the grounds of nearby Koenji Hikawa Shrine (高円寺氷川神社), where it remains today as a sub-shrine — said to be the only weather shrine in Japan. It has become a popular destination for visitors praying for good weather, and its distinctive geta-shaped ema (prayer plaques in the shape of traditional wooden sandals) have made it a beloved local curiosity.