Please stop saying the Japanese are descended from Koreans

When I was attending middle school in Korea in the late 1980s, we were taught that Koreans were the genetic and cultural progenitors of the Japanese; more specifically, that in the first few centuries AD, the civilized Koreans introduced the barbaric Japanese to the bronze age, to rice cultivation, and apparently, to Korean DNA as well. Moreover, it was said, the Japanese royal family was descended from a Korean fifth-century King named Muryeong.

I didn’t buy it. Japan-bashing was woven throughout the school curriculum, inseparable from the Korean identity. Though primarily the Korean resentment arises from the Japanese colonial period (1910-1945), the hostility between the two nations is 700 years old and very mutual.

Thus, I just kind of assumed that these ancestry claims were one of those apocryphal Korean yarns, such as the uniquely Korean belief that sleeping while a fan is running and the window is shut will result in your death overnight.

Once I left Korea, “fan death” ceased to be a part of my life, but the the “Japanese are descended from Koreans” chestnut has resurfaced several times.

In 2001, for example, Japanese Emperor Akihito shocked his countrymen by saying casually in a press conference that his imperial line was descended from Koreans, thus confirming what I had assumed to be a Korean myth. He reportedly said, “I, on my part, feel a certain kinship with Korea, given the fact that it is recorded in the Chronicles of Japan that the mother of Emperor Kammu was of the line of King Muryeong of [the former Korean kingdom of Baekche].”

Koreans were hella excited, to which my response, basically, was “Whatever. Hooray for you guys.”

For many Japanese and Koreans, though, this announcement was a big deal (context: he was talking about the upcoming 2002 World Cup, which his nation was co-hosting with Korea). All Japanese Emperors historically had been considered gods; to wit, direct descendants of the sun goddess Amaterasu Omikami. In fact, the notion of imperial divinity didn’t end until after World War II, when Akihito’s father Hirohito famously renounced his divinity. And yet just a generation later, the son is admitting not only that he is not a god, but that he is descended from a peoples whom the Japanese have traditionally considered inferior.

The princess and the aborigine

Last year, in the process of writing an article about my 23andme genetic test results, I came upon a startling discovery: My genetic makeup was almost 14% Japanese (or so it seemed). Since my family is Korean, this discovery was inconsistent with the family narrative.

I would later learn the boring truth that this 14% figure didn’t necessarily denote mixed ancestry; just that I possessed genetic traits often found in Japanese people. But in the process of sussing that out, I made an unexpected discovery. In an interview about my genetic heritage with Professor Raymond St. Leger at the University of Maryland, he told me, “You can’t distinguish [genetically] between Japanese and Koreans, because Japanese are just Koreans who interbred with the local aboriginal people.”

This was the first time I’d heard a non-Korean make this claim. I asked him, incredulously, whether this theory of Japanese ancestry was a known belief amongst non-Koreans. He said laconically, “I’m English; I have no dog in this fight.”

Chinese literature, according to St. Leger, claims that “the Japanese are descended a Korean princess who married a very hairy man, who is assumed to be a Japanese aborigine. There is some controversy in Japan about that.”

I did some searching for “Koreans are descended from the Japanese” and turned up a slew of stories, some in English, which all had headlines similar to this one: “DNA Analysis Confirms Japanese Are of Korean Descent.”

I was suspicious.

For one thing, all the articles seemed to be traceable to a single ur-source, an article in Yonhap news (link in Korean).

The articles referred to a 2011 Japanese academic paper. I hunted it down, and contacted the geneticist who authored the paper, Dr. Noryua Saitou. I emailed asking him for an interview about his findings that Koreans are the ancestors of the Japanese.

I was stunned by his reply: “We did not report such ‘findings’. Please ask some other researchers.”

I got someone to translate his paper for me. Nowhere does Saitou’s article say that Koreans are progenitors of the Japanese.

In fact, there is only one mention of Koreans the article: “Koreans share the same SNP (Single Nucleotide Polymorphism) clusters as do the middle-island Japanese.”

Of course, this doesn’t mean the Korean claim is false [or true, for that matter], only that the article in question had drawn a false syllogism and misrepresented one scientist’s work. Still, shoddy.

The global stakes

Every nation clings to its own version of itself. None of this would matter, really, except for the pesky reality of geopolitics. North Korea is behaving more Bond villain-y than usual, and the US wants South Korea and Japan to unite against North Korea.

If global stability and the threat of nuclear annihilation requires South Korea and Japan to get along, erm… they probably will, but whilst they smile for Westerners, under the surface, bad blood runs hotly and always.

Myong-ja Park provided translations for the Japanese-language materials mentioned in this article. Learn how to write for Quartz Ideas. We welcome your comments at ideas@qz.com.

home our picks popular latest obsessions search