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Because battery sizes are defined by international standards, Japanese-made batteries can be used in most overseas electrical devices. However, naming conventions differ by country—for example, what are called size D and size C in the United States correspond to Japan’s size ‘tan-1’ (AA-size equivalent: no) and ‘tan-2’ respectively.

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“Bakushō” is defined as “a large group of people bursting into laughter, or that kind of laughter,” so while you can laugh out loud by yourself, you cannot have “bakushō” alone.

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The manufacturing cost of a 1-yen coin is about 3 yen and that of a 10-yen coin is about 13 yen, both exceeding the face value of the coins, whereas a 50-yen coin costs about 12 yen to produce, making it cheaper than the 10-yen coin.

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1 mickey is 1/100 of an inch (about 0.25 mm). It is said that the most widely accepted theory is that Chris Peters, who worked as a programmer at Microsoft, jokingly named it after “Mickey Mouse.”

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The highest rank is 10th dan, and the belt is red. The belt colors for dan holders are standardized nationwide: 1st through 5th dan wear black belts, 6th through 8th dan wear red-and-white belts, and 9th and 10th dan wear red belts.

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The groove at the tip of a toothpick is often said to serve as a non-slip feature or a rest for a used toothpick, but in fact it’s neither. During manufacturing, when the tip is sharpened, the wood on the end you hold can get scorched by the machine’s high-speed rotation, so the discolored part is simply shaved off for appearance’s sake. In other words, the groove carved into a toothpick has no particular meaning or use.

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The one that doesn’t exist is the surname “Mirin.” All the others are real family names, and many of them are said to come from origins like making sugar (hence Satō, “sugar”) or managing a miso storehouse (hence Miso), and so on.

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Proceeding through a red light is permitted during emergency response, but parking violations apply even to patrol cars while they are enforcing the law.

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When scissors are inserted into glass underwater, water molecules composed of hydrogen and oxygen rapidly penetrate the crack and sever the bonds between oxygen and silicon that make up the glass. This phenomenon is called the chemomechanical effect.

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The potted plants in banks are placed to provide a reference for a robber’s height if one comes in. Their height is standardized at around 170 cm. This measure is used because, while people can often describe noticeable features like clothing at a glance, it’s difficult to clearly state a person’s height.