(Friday Night History) Inō Hanzaemon’s Long Walk

80-yen memorial stamp of Inō Tadataka. (Image PD)

Last week, we looked at Mamiya Rinzō, his surveys of Ezochi– the land we now call Hokkaido, Sakhalin, and the Kurile Islands– and how they aided the Shogunate’s efforts to bolster its control of the march to the north of Honshu. We also learned how this was tied up in the Siebold Incident. Mentioned along the way was Mamiya’s teacher, Inō Tadataka– alias Inō Hanzaemon– and his own epic survey of the Japanese coastline. Unfinished at the time of Inō’s death, Mamiya finished it and saw it to publication. This week, we’re going to explore more of Inō’s story, and round out our appreciation of the man, his career, and his oeuvre. I should note here that last week I kept flubbing his name– it’s Inō, not Ina– this week, I’m getting that right.

Okay, so Inō Hanzaemon was born in Ozeki, a village of Kazusa Province, which today is part of Kujukuri town, in what’s now Chiba Prefecture. He was adopted by a wealthy family of sake brewers and rice dealers of Sawara in nearby Shimosa Province– today part of Katori, Chiba Prefecture– which is how he received the Inō surname. At that level of financial privilege, the distinction between a merchant and a warrior was a lot blurrier than might be assumed, which is important to bear in mind considering that he went on to work for the Shogunate and is often depicted with not one but two swords, which is a well known mark of the warrior caste in Edo period Japan. He was wealthy enough that he was able to use his own funds to provide relief for the local population, which was suffering the brunt of the Tenmei famine, and to have his own wealth not particularly adversely impacted. And, this financial privilege also afforded him the stability and freedom to engage in self-study of calendar making and astronomy.

A word on that point of astronomy. Some of you might remember one of the more popular earlier episodes of Friday Night History– long before it was a podcast– in which I talked about the imperial court’s Ministry of Divination– a sort of real-life Ministry of Magic which existed until 1873. While its purview did indeed center on matters surrounding the occult, it was also the bureau which handled things like calendar making, astronomy, weather forecasts, and more– all of these very real-world sciences were important to how it did its work. So the Shogunate, as with the imperial court, had its own astronomers and calendar makers, who were aware of the work of the Ministry, but had less of an emphasis on the occult. And so at age 49 in 1795 (Kansei 7) Inō went to study with one of them, Takahashi Yoshitoki. Again, it was Inō’s financial privilege that allowed this– he was not only wealthy, but by this point, he’d already retired as a successful businessman, passing on the family headship and business while retaining access to the family’s wealth with which to fund his own studies.

This is the part that I keep getting stuck on, as I research and write this story. The Tenmei Famine killed and impoverished a lot of people, and this was also the era of rice speculators hoarding rice from starving people and triggering the direct action called “smashings” (uchikowashi) where angry, starving people smashed their doors in and carried off the rice. So the thought that Inō had the money to independently do a survey of this magnitude, in a time when so many others were suffering, haunts me.

For better or worse, Inō spent five years furthering his political and scholarly connections in Edo as well as advancing his personal studies. At the end of it, the Shogunate approved his plan to survey the Japanese coastline, and Inō set off on the first of what was eventually a series of ten surveying missions. The Shogunate endorsed the mission, given– as we saw in last week’s episode– the rising threat posed by the Russian Empire’s incursions to the north. It wasn’t long before this, after all, that Russian envoy and military officer Adam Laxman visited Japan in an attempt to negotiate concessions including a trade agreement. But the Shogunate was also dealing with its own recovery from the Tenmei Famine, and I’m sure it was all too glad to let Inō do the survey as long as he picked up the cost himself. These surveys took him and his team around to all the extremes of Japan. Inō surveyed the Japanese coast, as well as much of the coastline of neighboring Ezochi, with surveying instruments of his own invention.

As an example of Inō’s work, let’s take a look at this snippet, which I’ve snapshotted from the maps in the collection of the US Library of Congress. For listeners, check out the blogpost for the image. For reference we’re orienting ourselves with West to the top in the interest of text direction.

Sendai section of the Inō Taizu. (Image PD)

To the top of the image is the spine of the Ōshū Mountains. Below them, along some smaller hills, rise castle walls– Sendai Castle, on Mount Aoba– with the legend “Residence Castle of Lord Matsudaira Masachiyo.” House Date had the right to use the Matsudaira surname, the original name of the Tokugawa clan, as an honorific– Masachiyo was the childhood name of Date Chikamune, the then-lord of Sendai domain.

Below, in a red zigzag, the line of the Ōshū Highway runs left (south) to right (north). Nagamachi at left, Nanakita at right, both part of the modern city of Sendai. The county line between Natori County and Miyagi County is clearly delineated– here, it follows the line of the Hirose River, on the left. Pretty much all of what we see here is part of modern Sendai, and this stretch of the Ōshū Highway roughly overlaps with the line of the Tohoku Shinkansen, the Tohoku bullet train.

Inō’s survey work was so gradual and monumental that along the way, others joined him and even became his students. One of these was Mamiya Rinzō, about whom we talked last week– to get his story, go back and listen to Episode 25: Mamiya Rinzō Goes North. Mamiya came from similar affluent non-warrior roots as Inō, and as we discovered, went north from what’s now Wakkanai with Matsuda Denjūrō in tow to map the coast of Sakhalin, which at the time was thought to be a peninsula connected to the Asian continent, but which thanks to Mamiya’s survey was proven to be an island.

An early pedometer used by Inō. (Image PD)

In 1812 Mamiya returned to Ainu lands to finish the unfinished work of Inō, together with others of the latter’s friends and students. Inō died in 1818, at age 73, which was extremely long-lived for the time. But the work of Mamiya and others made possible the 1821 presentation to the Shogunate– and original publication– of Dai Nihon Enkai Yochi Zenzu, Inō’s coastal mapping survey. You can check out Inō’s Dai Nihon Enkai Yochi Zenzu here, digitized and viewable in the collection of the US Library of Congress https://www.loc.gov/item/2001620020/ — for the podcast listeners, check out the blogpost and follow the link. It’s big. It’s also apparently one of the most complete surviving collections of the entire series anywhere in the world.

As noted last week, the work of both Mamiya and Inō was crucial to the Tokugawa Shogunate’s development of coast defense nationwide as well as policy on the northern border, in and beyond the march controlled by the house of Matsumae. As such, it was deeemed strategically sensitive information, which is why the Shogunate reacted so severely when in 1828, the Prussian doctor Philip Franz von Siebold, then posted to Dejima in Nagasaki harbor at the Dutch East India Company’s outpost, was found to be in possession of copies of Mamiya and Inō’s maps in what is remembered as the Siebold Incident (Shiiboruto Jiken シーボルト事件). The maps continued to inform Japanese cartography for nearly a century, well into the late Meiji era.

Inō’s former residence is preserved as a museum in what’s now Katori, Chiba Prefecture, where across the street can be found the Inō Tadataka Memorial Museum, which preserves documents as well as some of the surveying equipment from this monumental undertaking. If you’re in the area, or are listening one day when it’s possible to enter Japan again, go and take a look!


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