A piece of fan-made merchandise for Uma Musume: Pretty Derby, slated for sale at Japan's Comic Market (C108), was abruptly pulled after it was discovered to be in potential violation of Japan's Measurement Act. The item in question? A ruler featuring both centimeter and inch markings.
The creator, a Korean artist, decided to withdraw the product just before the event, sparking a flurry of discussion among Japanese netizens, many of whom were shocked to learn about the law: "Wait, there's a law that restricts selling rulers with inches on them in Japan?!"
Korean artist sarcophage had planned to sell a custom "Oguri Cap & Tamamo Cross Acrylic Ruler" on the first day of C108. The item was designed as a desktop acrylic stand that also functioned as a ruler.
The product featured both centimeter (cm) and inch scales and cleverly incorporated Oguri Cap's tail as a pen holder. When the item was revealed on August 7, it generated significant buzz, with many fans planning to pick one up at the event.
However, in the early hours of August 8, sarcophage suddenly posted a "Notice of Distribution Halt," announcing the withdrawal of the product planned for C108.
The artist explained that, being from Korea, they were unaware of Japan's Measurement Act. The ruler could potentially violate this law and lead to fines, prompting the decision to cancel its sale.
Shortly after the product was announced, some fans looked into the matter and pointed to information from Japan's Ministry of Economy, Trade and Industry, noting that the country's Measurement Act has strict regulations on measuring instruments that use non-statutory units.
One user warned that if a product is explicitly sold as a "ruler" and displays both cm and inch markings, it could be a violation, potentially resulting in a fine of up to 500,000 yen.
Another netizen directly cited Article 9 of the Measurement Act, which states that measuring instruments intended for specific physical quantities are, in principle, prohibited from being sold or displayed for sale if they include scales or markings in non-statutory units.
In other words, the issue wasn't simply about whether fan merch could have inches on it, but whether the product would be legally classified as a measuring instrument for length.
As news spread, many expressed their complete surprise, admitting they had no idea this regulation existed. "So selling a ruler with inch markings in Japan, whether it's commercial or fan-made, is illegal... I genuinely didn't know that," one person commented. Others felt it was an unfortunate situation for the creator, as it's a law that even many Japanese people are unfamiliar with.
However, online discussions also highlighted that the presence of "inch markings" doesn't automatically mean "illegal." After checking the Ministry's FAQ, some users found that if a product is sold as a toy or a decorative item rather than an actual measuring tool, it may not be subject to the same restrictions.
This led some to point out that products with inch markings have appeared on the market before, likely because they were classified as toys or for other purposes, not as official measuring tools. Another theory emerged: the real key might be the explicit unit labels like "cm" and "inch" on the product.
If an item only has numbers and tick marks, it could be considered a design or pattern. But once you clearly label the units and market it as something that "can be used as a ruler," the product takes on the properties of a measuring instrument.
What started as a fan creator's attempt to make a more practical piece of merchandise—adding a ruler function to an acrylic stand—unexpectedly ran into a little-known provision of Japan's Measurement Act due to its "cm + inch" markings and its positioning as a usable ruler. The incident served as a surprising lesson for many in Japan, revealing that selling a ruler with non-statutory units like inches isn't as simple as one might think.