Hirase Sakugoro (平瀬作五郎)

Sakugoro HIRASE (February 12, 1856 - January 4, 1925) was a botanist in the Meiji and the Taisho periods.

He was born in Fukui City. In 1875, he became a drawing teacher and moved from place to place. In 1888, he was employed by the College of Science, Imperial University of Tokyo, and in 1890 became a research assistant there. His job was mainly to draw pictures, from which he developed an interest in botany. When he was a research assistant at the botanical laboratory of Imperial University of Tokyo, he identified spermatozoids of ginkgo first in the world.

He discovered the spermatozoids of ginkgo in January 1894, before Seiichiro IKENO discovered the spermatozoids of cycad. Shortly after he was promoted to a research assistant from a drawing technician at the botanical laboratory of Imperial University of Tokyo, he showed to associate professor Seiichiro IKENO, spermatozoids of ginkgo, which he found but mistook for some parasite worms. At first glance, IKENO recognized them as spermatozoids intuitively. On September 9, 1896, HIRASE "witnessed sperm dashing out of the pollen tube and moving around vigorously, " and published a paper titled "Spermatozoids of ginkgo " in October. This was the first discovery of gymnosperm spermatozoids in the world and his discovery as well as Seiichiro IKENO's discovery of cycad spermatozoids was the most remarkable contribution to botany made by Japanese people.

One year later, Sakugoro HIRASE was transferred out to Hikone-higashi Prefectural High School of Shiga and had to abandon his research once, having a hard time. In 1912, however, HIRASE, together with Seiichiro IKENO who can be said to have been his mentor, was awarded Onshi Prize (the Imperial Award) (by the Japan Academy), for their highly evaluated discoveries of gymnosperm spermatozoids and cycad spermatozoids respectively. It was quite unusual that Onshi Prize was given to a person like HIRASE having almost no academic background. Although Sakugoro HIRASE was not initially included in prize recipients, Seiichiro IKENO said, 'I will refuse to receive the prize if HIRASE is not given the prize,' and as a result, both received the prize.

The ginkgo tree, from which Sakugoro HIRASE discovered the spermatozoids, is still preserved inside of Koishikawa Botanical Gardens in Hakusan, Bunkyo Ward, Tokyo, with a stone monument erected in commemoration of his discovery.

He taught at Hanazono Junior and Senior High School in the latter half of his life. He died at Omuro in Kyoto.