triangulated by modern surveyors.
1880 August: Thomas Mendenhall weighs the earth by conducting gravity experiments on the summit, assisted by Tanakadate Aikichi and others. So accurate is the pendulum clock he devises for this purpose that a similar one is later used to measure the speed of light.
1889: Nakamura Kiyo'o and Kondō Hisajirō make a 38-day series of weather observations respectively from a stone hut on Kusushi-dake, one of the eight peaklets around the crater of Mt Fuji, and from beside Lake Yamanaka.
1895: officials from the Central Meteorological Office take readings on the summit during the summer. They too use a hut on Kusushi-dake. In the following winter, independent meteorologist Nonaka Itaru attempts to overwinter in a self-built summit hut under Ken-ga-mine, the highest summit, supported by his wife Chiyoko. They endure the cold and beri-beri for 82 days, before being rescued in December.
1927: meteorologist Satō Junichi builds a summit hut for weather observations, supported by a grant from Suzuki Seiji, president of the Tokyo School of Motoring.
1930 January-February: now in his fifties, Satō Junichi overwinters in his summit hut, supported by porter Kaji Fusakichi, proving that round-the-year weather observations are possible. Kaji will go on to climb Mt Fuji a record 1,672 times during his lengthy career.
|Inaugurating the Mt Fuji observatory on August 1, 1932|
1934: the future of the summit observatory is secured by a grant from a foundation recently established by the Mitsui zaibatsu after a right-wing extremist had assassinated its director-general Takuma Dan.
1936: now officially styled the Mt Fuji Summit Observatory of the Central Meteorological Office, the observatory is moved from Yasu-no-kawara, a flattish area on the crater's south-eastern rim, to a new building on the mountain's highest point, Ken-ga-mine. In the same year, physicists from Nishina Yoshio's research group at Riken visit Mt Fuji to study cosmic rays.
1944: a squad of soldiers run a high-tension cable all the way from Gotemba to the summit to power a wireless relay station. The summit weather station also gets a direct electricity supply for the first time.
1945, July 30: the summit station is attacked by two enemy fighters. Some of the staff are injured by flying debris. This is the most damaging of three strafing attacks on the summit installations during the last two years of the war.
1964: the weather radar station is completed on Ken-ga-mine after a dramatic helicopter lift to bring in the surmounting radome. In the following year, the post office issues a 10-yen commemorative stamp and the radar tracks its first typhoon.
1985: the radar is upgraded with digital signal processing and colour output display.
1999 November: the radar is shut down and the famous radome is later taken down to a museum at the mountain's foot. From now on, typhoons will be tracked by satellites and two newer radar stations, one at Makinohara in Shizuoka and the other on Kurumayama in Nagano.
2004, October 1: the manned weather station closes too, ending 72 years of continuous human habitation on the summit of Mt Fuji. Automated instruments will continue to relay meteorological observations from the summit to a base station.
This timeline is adapted from the one on the website of the Society for the Valid Utilization of Mt.Fuji Weather Station, an NPO that seeks to preserve the buildings of the summit station for continued scientific activities. Additional information is from (ed) Dokiya Yukiko, Kawaru Fuji-san Sokkojo, 2004.