Koshigaya        35°54’59"N, 139°46’51"E

Kanto, Japan

Confirmed fall: 1902 Mar 8

Classification: Ordinary chondrite (L4)

History: Around dawn on March 8, 1902 (the date is confirmed by the Tokyo Asahi Newspaper on April 25, 1902), a detonating sound was heard at the Sakurai-mura, Minami-Saitama-gun (now the Koshigaya city), Saitama prefecture, Japan. A few days later, Mr. Kihachi Nakamura found a 4 kg stone from ca. 1m depth of the meteorite pit found in his own farm. Since then, it was kept in the Nakamura family. Through a society for the study of the local history in the Koshigaya city in 2021, the stone was brought to NMNS, where cosmogenic ²⁶Al gamma rays were detected by the pure Ge detector and it was confirmed as a meteorite.

Physical characteristics: The 4050 g mass is roughly rounded form and is almost fully covered by the fusion crust. A small portion is lacking probably due to the crash on the ground.

Petrography: A polished thin section and a polished mount were made from a 1.9g fragment at NIPR.

Geochemistry: Olivine Fa_24.9, range Fa_22.3-26.1, Fa PMD 2.1% (N=35). Low-Ca pyroxene compositions are Fs_17.4Wo_1.2, range Fs_9.4-27.2, Fs PMD 20.4% ( N=14). Gamma ray measurements at NMNS did not detect show the absence of ²²Na (half-life 2.6 y), suggesting that the fall date was more than a few tens of years ago. Rare gas analyses are underway at KyuU.

Classification: Ordinary chondrite (L4, S2).

Specimens: NMNS: 120 g for Type specimen; NIPR: polished thick and thin sections