STORYIKKANSAI KUNITOMO

Ikkansai Kunitomo was born on Octobor 3rd 1778 in Kunitomo Village in Sakata-Gun of Ohmi Province (modern day Kunitomo-town in Nagahama City, Shiga Prefecture). His childhood name was Toichi but after taking over the family name at 9 years old in 1786 he took the name Toube. For personal use he also used Ikkansai, Minryu, and Yoshimasa as pen names. He etched many of these aliases into his various inventions and knick knacks.

Atsutane Hirata, who taught Ikkansai many things about science and technology, gave him the nickname Yoshimasa (能当). This comes from the Japanese “能く当たる” meaning to “hit well” in reference to a matchlock bullet. Ikkansai’s real name was Jyukyo and he often signed his letters as such.

Ikkansai made many achievements in science and technology. This is an introduction focused on his work with matchlocks and air guns, reflecting telescopes and his observations of space.

Ikkansai was the first person in Japan to build an airgun. In 1814 an eye doctor working for the Zeze Clan, Daien Yamada heard an account of a Dutch airgun. Shortly thereafter he had constructed a mock up of this airgun. On October 5th, 1818 Ikkansai, who was in Edo at the time, was shown the actual Dutch airgun by Daien Yamada. Daien Yamada had borrowed the airgun from the feudal lord of Tangomineyama, Takamasa Kyogoku, because the airgun was in pieces and neglected as there were no craftsmen capable of fixing it.

Ikkansai was commissioned on the spot to restore the airgun which he did over a short period of time. While working he recorded and sketched out the designs of the airgun but wasn’t satisfied with the performance and thought that he could create a better design.

On November 1st, Ikkansai started work on his original design and gave Takamasa Kyogoku the finished product on March 9th the following year. He also included a instruction manual showing how to use his air rifle. At first it appears he planned on making the air rifle with a caliber of 3.5 monme but ultimately the rifle he gave had a caliber of 1.5 monme (about 1.1 centimeters).

On May 24th 1819, Ikkansai gave a demonstration of his new firearm to the feudal lord of Wakasa Obama and roju, Tadayuki Sakai. There is an illustration of this event in the Ikkansai Archives. On the following day Ikkansai gave a demonstration to the fuedal lord of Mino Iwamura and roju, Noriyasu Matsudaira.

On June 20th, 1832 after returning home from Owarinokuni, Ikkansai started work on his reflecting telescope. Zenbe Iwahashi of Kaizuka Izuminokuni had completed work on a refracting telescope and made astronomical observations in 1793. In 1796, Koukan Shiba published the Oranda Tensetsu introducing the sun centered theory of the galaxy. At that time intellectuals interest in space was at a peak. It is thought that Koukan Shiba, while in Edo, acquired his knowledge of heavenly bodies from Atsutane Hirata’s group of pupils. In particular, the dutch made telescope Telesukofu Omegane in the estate of Masanaga Naruse, the feudal lord of Owari Inuyama, served as a great encouragement to him. Making this telescope as well as a Gregorian Reflecting Telescope where longstanding desires of his.

Ikkansai mostly finished his reflecting telescope by 1833. Unlike the refracting telescope made by Zenbe Iwahashi the reflecting telescope made by Ikkansai was the first in Japan to make use of mirrors. He continued to build these reflecting telescopes until 1836. Four of these are still in existence.

What Ikkansai had the most difficulty with while constructing the telescope was first the casting of the reflector, second the polishing of the mirrors and third the polishing of the glass lenses. According to information handed down Ikkansai was gradually improving the telescope while studying the stars. The result of this was the production of a mirror that he predicted wouldn’t get foggy after 100 years. Through polishing he was able to successfully shape a parabolic reflector. During his observations of the sun he developed glass purpose made for looking at the sun. Ikkansai’s telescope had a large impact on the astronomy section of the Shogunate as well as amazing Osaka’s private astronomer Hazamashigeyoshi with how, compared to the Dutch telescope, Ikkansai’s telescope had less haze and stars appeared to be double in size.

On December 3rd, 1840 Ikkansai passed away at 63 years of age. His creative genius in science as well as technology continue to shine even today. However, in those times there was noone in Omi Kunitomo to succeed him in blacksmithing. Also, there was noone to sponsor him to industrialize his ideas in science and technology.

Therefore, although it is unfortunate, there was noone in the region to inherit his skills. However, he was the person to raise the standard of modern Japanese science and technological prowess and therefore should be known throughout Japan more.