Demographics Professor Warns that by 2531, Everyone in Japan Will be Named Sato

image courtesy Mainichi Shimbun

Despite today’s date, this is not an April Fool’s prank. At a press conference in Tokyo last weekend, professor Hiroshi Yoshida from the Tohoku University Research Center for Aged Economy and Society, sounded the alarm bell for a looming crisis. By the year 2531, everyone in Japan will have the surname Sato.

image courtesy ANN News

Professor Yoshida presented his research findings, which included a recent demographic study analyzing the growth rate of the Sato surname. Already Japan’s most common surname, 1.5% of Japan’s entire population have the name Sato. Furthermore, between 2022 and 2023 the surname displayed an alarming growth rate of 0.83%. If this rate continues, it could trigger a snowball effect that would eventually lead to what Professor Yoshida has dubbed the “2531 Sato-san Problem.”

To tackle this crisis, Professor Yoshida has spearheaded an initiative called the ThinkNameProject to raise awareness of the issue. Below is a video they created:

Of course there are many assumptions that went into Professor Yoshida’s analysis (methodology is linked here as a PDF, but is in Japanese), including the assumption that Japan never amends their law that mandates married couples share the same surname. In fact, Japan is the only country with a law forcing couples to adopt the same surname after marriage. Given that more than 95% of wives in Japan take their husband’s surname, the single-surname rule not only drives down the diversity of surnames but also adds fuels to the fire of gender inequality.

ThinkNameProject is hoping that politicians will finally bend under the pressure to address the 2531 Sato-san Problem and revise Japan’s outdated law that prohibits separate surnames.

a hypothetical chart shows the snowball effect of the Sato surname growth rate | image courtesy ANN News

image courtesy ANN News


  1. Fascinating. But if nothing about the declining birth rate changes there will only be 10 million Japanese people in 2200 so a 2531 prediction falls into the category of deep silliness. Still one can appreciate a good statistical analysis.

  2. If Japan’s government doesn’t start recognizing LGBTQ+AP rights, they could be looking at being taken over by the United Nations. We, the international community, will not stand for these games that are being played by the Japanese.

    • Yoshiro Matsukaze

      April 2, 2024 at 3:59 am

      Then sit for it because you’re not going to be able to do shit about it.

    • Why should they accept it. Do not force what people don’t want. You people did not accept yourselves in the first place, so do not think people will do, and if you are so “inclusive” then accept also their opinions about it. It’s so funny to me that everything has to spin around you, doesn’t matter the topic.

    • No one cares about that lol. Like 2% of the population

    • You’re words are bigoted, please understand how wrong you are, thank you.

      • Also everyone else in this thread is a homophobe. I’m incredibly disappointed the overwhelming response to this was ‘hurr durr me no like gay’ instead of pointing out how stupid a UN invasion of Japan is.

        Nobody’s saying you have to like gay people, just don’t be rude or violent. The bar is that low, but so many people insist they can’t possibly meet it.

    • OP, that’s literally the dumbest political opinion I’ve ever read on any website ever. You have absolutely no idea how anything works and should never be listened to under any circumstances. If I were you, I’d be too ashamed to even consider sharing any opinion in the future ever again. Whenever you leave your hometown, the average IQ shoots up at least 10 points. This response alone is dumb enough to convince anyone that the Dead Internet theory is real because there is no other explanation for such a stupid and blatantly incorrect opinion being posted here. I hold people who think Trump won the last US election in a higher regard than you, and I call those people stupid to their faces IRL.

      1. The UN doesn’t take over countries.
      2. Even when it intervenes, it’s notoriously shit at stopping bad things from happening (ask Rwanda how the Tutsis are doing)
      3. Even if it did intervene and could do it competently, Japan is far from the most homophobic UN member.
      4. This article is about name laws, not LGBTQ laws.
      5. Marching into another country and announcing you’re now in control of them is called ‘starting a war’. The point of the UN is ‘war is bad so let’s do diplomacy instead’.
      6. China and Russia are permanent members on the UN security council. Ignoring every other point here, they both would have the power to veto such an action, and it would be in their own best interest seeing as they also have strict laws against being gay.
      7. If they couldn’t veto it and the UN went to war against everyone who doesn’t legalize gay marriage, that’s going to be a US + Europe vs Asia + Russia situation, two blocks of nations that are currently terrified of open war with each other because they all have nukes and are dumb enough to use them. Where the fuck have you *been* for the past decade and why the fuck do you think the US is currently in a proxy war with Russia in Ukraine instead of declaring war outright?
      8. Fuck you for making me type all this. I need you to understand just how fucking dumb and uninformed your opinion is. You can’t be this dumb in real life, if you were you’d need round-the-clock care.
      9. Even if the UN takes over Japan and changes the laws, either the UN pulls out after making the changes and the new Japanese government rescinds the changes and Japan fights against them harder out of spite, or the UN occupies Japan indefinitely until there’s a revolution and/or the UN as a body overreaches it’s power and is dissolved, at which point the new Japanese government rescunds the changes and Japan fights against them harder out of spite.

      Congratulations, you’ve steered the world into nuclear war and caused the destruction of the UN with your shitty ideas. If you ever go into politics, let me know so I can shoot myself first so I never have to see the horrors you inflict on society.

  3. my imagination has led me to think there will be no need for marriage if everyone has the same family name…… no easy identification of ‘rule breakes’ by their family name ……. a step on the way to equality hmm! haha!

  4. To me, the options seem to be still open – when women can keep their name, the Sato problem is then simply transferred to the children, isn’t it? When the mother keeps her name, then it’ll be important whose name will be given to the couple’s kids. If it’s the fathers name Sato in this case, it doesn’t help. It would only help if the couple could choose the mothers name to be given to the kids (as long as her name is not Sato).

    How does Japan rule the childrens names in case of a couple with different names?

  5. I think it would be a good thing that couples should no longer have to choose whose surname they’re keeping, but I fail to see how that is going to stop the Sato-San snowball effect.
    As long as any children from a Sato-couple receive the surname of Sato, regardless of whether it’s the mother’s or father’s surname, the number of Sato’s will continue to expand.
    The only solution seems, indeed, to stimulate couples where one of the partners has the Sato-surname , to give the children the name of the other partner .

  6. When Professors are too busy with their side hustle and realize they need to publish to keep their tenure.

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