[1][2] Yoichirō greatly contributed to the start of malacology in Japan and was responsible for the collection and indirectly the naming of many land and marine mollusks.

He was a wealthy Kyōto dealer in poultry, seeds, and aviculture products who had founded a side business trading in marine and land shells.

He coordinated numerous field collectors to explore the territories and prefectures of Japan gathering both land and marine mollusks.

[3][4] Many of the species found by his team were newly discovered and named in collaboration with many scientists around the world, including H.A.

Kuroda's employment initially included cleaning Hirase's large house and looking after his children by day.

A rapid learner and diligent clerk, Kuroda was soon placed in charge of the shell business, and became Hirase's secretary.