Official

The place where Tadataka once settled in his later years is at the exit of Kayabacho Station in Chuo-ku. At this place, the "Dainippon Seaside Koshichi Map" was also created, but Tadayoshi died without seeing its completion. It was 1818, 202 years ago.

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

Tadayoshi Statue of Sahara Park in Katori City, Chiba Prefecture 2018

After reading some books, I thought that loyalty's life could be roughly divided into three.

　①A period of success as a merchant in Sahara
　②The era when I dreamed of a teacher, Yoshitoki Takahashi in Edo
　③Late years of walking toward the completion of the map

The turning point of loyalty was undoubtedly when he came to Edo at the age of 49, at the border between 1 and 2. Tadayoshi, who gave up his family and retired and loved studying, set up his home in Kuroe-cho, Fukagawa, Edo, and became a disciple of Yoshitoki Takahashi, the shogunate's astronomy.

Remains of residence in Fukagawa, Koto-ku

He had just come out to Edo at the time of the time, and they met as if they had shown each other, but since he left a will to bury them near the time of the time, the encounter with the time was definitely the best for his lifetime.

Tadataka goes to Asakusa Observatory to study calendar and astronomy that he was interested in. I gradually came to think, "I want to know the size of the earth." He had the same thought at the time of his master, but in order to realize it, he needed to measure the long distance between the north and south.

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

Site of the Shogunate Observatory in Taito Ward

When he was 19 years younger, he recognized his loyalty and ability. And I thought that if I let him make a map of Ezochi, which was pending in the Shogunate at that time, I could measure the earth.

They work hard to realize their dream of "want to know the size of the earth." And he managed to turn to Ezochi. Tadayoshi At the age of 56 (first survey).

It was a survey for map creation on the face, but the real purpose for loyalty is to measure the earth. I was absorbed in what I was interested in. From an ordinary person's point of view, it seems like a very difficult job, but he may not have been conscious of trying hard or doing patiently. I think that the difficulties and stress of traveling were rather materials that could be done while turning them into fun.

His surveying technology was 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 the stars were observed at night to correct the survey errors. In addition to the Arctic stars, it also keeps records of astronomical phenomena such as lunar eclipse and solar eclipse.

Statue of loyalty 2018 in the old house of Sahara

The map created in this way is evaluated by the Shogunate. After that, it developed into secondary and tertiary eastern Japan surveying, and the length equivalent to 1 degree latitude was derived to 28.2 ri.

On the other hand, during the fourth survey, Tadataka deciphered a new Western astronomical book when he was doing the fourth survey, and learned that the latitude of 1 degrees was close to 28.2 ri, and the result of his loyalty proved correct.

It is said that he shared his joy with tears. It was the moment when their dreams came true, and at the same time, the map made proved accurate.

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

Ueno Gensoku-ji Temple, lined with loyalty and graves at the time of the supreme.

Four years have passed since I started surveying.

If there was a time to quit making maps, it might have been this time. One dream come true and the teacher loses. He was old, and his disciples grew up.

Unfortunately, I couldn't understand the feelings of that area even if I read the book. However, as I was recognized every time I surveyed, my interest was directed toward a magnificent one called "Completion of maps all over Japan", and I felt that my heart was already ready. I was sure there was Kodawari in making the map, and I was absorbed in it.

At that time, a happy event happened. The map completed by the eastern Japan survey up to the 4th was displayed on Shogun Ienari. Perhaps Ienari was admired by the workmanship, and then a warm hand was given by the Shogunate.

Tadayoshi was collected by the Shogunate, and subsequent surveying in West Japan was under the direct control of the Shogunate. The number of survey members increased, and the support of the Shogunate increased.

Taking this great opportunity, he went on to survey in West Japan without hesitation. 5th survey. At this time, he was already 60 years old. Now, is it about 85 years old?

Thanks to the support of the Shogunate, cooperation in places to visit increased. The number of members increased, making it easier to survey.

But the miscalculation for him was that it took time to survey West Japan. The coastline of West Japan was too complicated. After this, it will take 13 years to complete the survey.

Inozu, near the current Shimanami Kaido

13 years. It's a very long time.

What I wanted to know most about loyalty?

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

It's very difficult to continue. Especially when I'm lonely.

Even if you like it, if you do it for work, you will not be able to enjoy it honestly. Perhaps they wanted to quit by repeating the 6th, 7th, and 8th.

But he had a lot of understandingrs. I can continue because there are people around me. I have to keep going because there are others. An understanding person who has fulfilled his dream after death. It is very enviable that such an understanding person was around him.

And above all, did you feel very grateful for being able to work?

Statue of Soyamisaki and Rinzo Mamiya 2018
The northern half of Hokkaido in Inozu is based on his survey.

After the 10th survey, map creation began at my home in Kamejima-cho, where I was moving, but I breathed before completion. Three years later, the map by Tadataka Ino was completed. It was a late year supported by many collaborators.

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

Tomb of Ueno Genku-ji Temple and Tadataka

<Reference Book>
Tadataka Ino, a foolish person who first measured Japan
　　　　　Hoshino Yushozangawa Publishing 2010
National Survey of Tadataka Ino
　　　　　Ichiro Watanabe Tadataka Ino Study Group 2009

A few years ago, when I returned to my parents' home in Saitama and organized the old materials, strange things came out. This is a leaflet of the Ikebukuro Sunshine Planetarium that I attended from elementary school to high school.

At that time, I thought I went to Ikebukuro because I liked stars, but now I think it's probably different. I was impressed by the Galileo's story I saw when I was taken by a friend for the first time, and perhaps I was swayed by the train with the desire to know such a human story again. At that time, I met Tadataka Ino. My favorite historical roots are the story of Galileo and Tadataka Ino who met at the planetarium.

But regretfully, I can hardly remember the story of loyalty. Tadayoshi liked to see the stars, and the map was made by walking and looking at the stars. That's about it.

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

Remembering that, I'm sure I'll be able to unlock my dream at this age. I would like to thank this blog for providing me with such a place.