Official

The place where Tadataka once settled in his later years is located at the end of Kayabacho Station Exit 1 in Chuo-ku. In this place, the "Dainihon Kaishichi Zenzu" was also created, but Tadataka left the world without seeing its completion. It was 1818, 202 years ago.

During the three years between his death and the completion of the map, his death was laid down. It is said that there was a desire of the people around me to make the achievement of the map perfection of loyalty. Imagining from such anecdote, it can be seen that loyalty was trusted and respected by others.

Charity statue of Sahara Park, Katori City, Chiba Prefecture 2018

After reading a few books, I thought that the life of loyalty could be broadly divided into three parts.

　①A period of success as a merchant in Sahara
　②A time when I dreamed with his teacher Yoshitoki Takahashi in Edo
　③His last years of walking toward the completion of the map

The turning point of loyalty was undoubtedly when he came to Edo when he was 49 years old at the border between 1 and 2. Tadataka, who took over the head of the family and loved studying, set up his home in Kuroe-cho, Fukagawa, Edo, and became a disciple of Yoshitoki Takahashi, a astronomy of the Shogunate.

Remains of dwellings in Fukagawa, Koto-ku

At the end of the day, they just came to Edo, and they met as if they had shown each other, but since they left a will to want them to be buried near the end of the day, there is no doubt that Tadataka had the first encounter with the time of his life.

Tadataka went to Asakusa Observatory to study calendar and astronomy that he was interested in. And gradually I came to a strong desire to know the size of the earth. Teacher: He had the same thoughts at the time, but in order to achieve this, it was necessary to measure the long distance between the north and south.

At that time, it was not allowed to measure without permission. However, Tadataka walked between the Asakusa Observatory north of his home and tried to find the size of the earth. But the distance was too short to measure the earth.

The ruins of the bakufu Observatory in Taito Ward

At the end of the age of 19, I recognize the enthusiasm and ability of such loyalty. And I thought that if he made a map of Ezochi, which was a concern in the bakufu at that time, he would be able to measure the earth.

The two work hard to realize the dream of "I want to know the size of the earth." And somehow, Tadataka went to Ezochi. Tadataka was 56 years old (the first survey).

It was ostensibly a survey for mapping, but the real purpose for loyalty is to measure the earth. I was obsessed with what interests me. From an ordinary person's point of view, it seems like a very difficult job, but loyalty may not have been conscious of trying hard or doing it patiently. I think that the difficulties and stress of travel were rather a material that could be done while turning into pleasure.

His surveying techniques were already cultivated during the Sahara period. The method was quite normal, but he had the ability to make various ideas in practical situations. What is characteristic is that stars were observed at night in order to correct survey errors. In addition to the North Star, he not only observed various stars, but also recorded observations of celestial phenomena such as lunar eclipses and solar eclipses.

Tadakei statue 2018 in the old house of Sahara

The map born in this way is valued by the bakufu. Later, the survey developed into the secondary and tertiary eastern Japan, and the length equivalent to one degree latitude was derived to 28.2 lit.

On the other hand, while Tadataka was doing the fourth survey, he deciphered a new Western astronomical book, and learned that the length of one degree latitude was close to 28.2 litres, and proved that the result of his loyalty was correct.

It is said that loyalty and time shared joy with tears. It was the moment when their dream came true, and at the same time the map was also confirmed to be accurate.

However, shortly after that, Yoshitoki Takahashi died suddenly. It is said that it was caused by overwork, who was too enthusiastic about deciphering work. What was the feeling of loyalty that lost his teacher at this time?

Ueno Genku-ji Temple, where Tadataka and his graves are lined up

4 years since I started surveying.

If there was a time to stop making maps, it might have been this time. One dream comes true and the teacher loses too. He was old, and his disciples were growing up.

Unfortunately, I couldn't understand the feeling of that area even if I read a book. However, as he was recognized each time the survey was repeated, his interest went to the magnificent thing called "Completion of Maps throughout Japan" and felt that his heart was already ready. Surely there was Kodawari in the map making, and I was obsessed with it.

At that time, a happy event happened. The map created by the eastern Japan survey up to the fourth stage was displayed by Shogun Ienari. Ienari was impressed by the work, and then a warm hand was offered by the bakufu.

Tadataka was taken up by the shogunate, and the subsequent survey of West Japan was conducted under the direct control of the Shogunate. The number of survey members increased, and the support of the bakufu increased.

With this great opportunity, I will proceed without hesitation in surveying West Japan. The fifth survey. By this time he was already 60 years old. So now, are you about 85 years old?

Thanks to the support of the bakufu, cooperation in places to visit increased. The number of members increased, and the survey became easier.

But his miscalculation was that it took a long time to survey West Japan. The coastline of West Japan was too complicated. After that, it will take 13 years for the entire survey to be completed.

Inou-zu, near the present Shimanami Kaido Road

13 years. It's been a very long time.

What I wanted to know most about loyalty is

“What was the driving force behind making maps?” “Did you really like it?” I'd like to ask you.

It is very difficult to continue. Especially when you are lonely.

Even if you like it, if you do it, you will not be able to enjoy it honestly. You may have wanted to quit by repeating the 6th, 7th, and 8th.

But he had many understandings. You can continue because you are around. I have to keep going because I'm around. Those who have made their dreams come true after death. I'm very envious that such an understanding person was around me.

And most of all, did you not feel so grateful for the job?

Statue of Soyamisaki Rinzou Mamiya 2018
The northern half of Hokkaido in the Inou-zu is based on his survey.

After the 10th survey, mapping began at his home in Kamejima-cho, where he had moved, but he died before completion. Three years later, the map by Tadataka Ino was completed. It was his last years supported by many collaborators.

Next year will be exactly 200 years from the completion of the map.

Tomb of Kozuke Genku-ji Temple and Tadataka

<Reference Book>
Tadataka Ino, a fool who measured Japan for the first time
　　　　　Hoshino Yusaoyamagawa Publishing Company 2010
National Survey of Tadataka Ino
　　　　　Ichiro Watanabe Tadataka Ino Study Group 2009

A few years ago, when I went back to my parents' house in Saitama and organized the old materials, something strange came out. It is a leaflet of the Ikebukuro Sunshine Planetarium, which I attended from elementary school to high school.

At that time, I thought I was going to Ikebukuro because I like the stars, but when I think back now, it is probably different. I was impressed by the Galileo story I saw when my friend took me for the first time, and I was probably shaken by train with the desire to know the story of such a human being again. At that time, I met Tadataka Ino. My favorite roots in history are the stories of Galileo and Tadataka Ino that I met at the planetarium.

But sadly, I barely remember the story of loyalty. Tadataka liked to see the stars, and the map was made by walking and looking at the stars. That's enough.

The planetarium, which I should have liked, ceased to last as I grew up.

I remember that, when I am old, I am going to open the key to my dream. I would like to thank this blog for providing such a place.