It’s a peculiar rule that even Japanese people don’t always understand.

You may know a few of the standard rules of Japanese society, like saying “Itadakimasu” before eating and taking off your shoes at the entrance of a house. But did you that when visiting someone’s home, it’s considered rude to step on the threshold of the doorway to a tatami room?

It’s a rule that has been ingrained in Japanese people’s subconscious as children, when they are often scolded harshly for stepping on the grooves of the sliding doors that open to Japanese-style rooms. Even foreigners might get some serious side-eye if they’re seen doing it, though we’re given a bit more slack, since we don’t know any better.

But what’s so bad about stepping on a doorway? Even Japanese people don’t know exactly why such a rule exists, but there are several theories. One is that, much like the difference between the inside and the outside of the house, the tatami room is seen as separate from the rest of the house, perhaps owing to the delicate nature of the mats, for one, and because the room is often reserved for traditional activities, like tea ceremonies, and praying at the family altar. As such, stepping on the threshold doesn’t respect that boundary and violates the sanctity of the space.

There’s also a much more fun theory about ninjas. Apparently, during more tumultuous times, ninjas would sneak under the wooden foundation of the house and lurk under the threshold, through which they could see the light of the room above. When the light was blocked out, they knew someone was standing on the threshold, and they used that opportunity to strike. Perhaps what was initially a habit of self-preservation eventually turned into manners as the risk of being attacked by ninjas decreased.

Of course, that story is a little bit hard to believe, because how successful would a ninja attack through the crack of a threshold actually be? On a more simple note, there’s also the idea that stepping on the threshold of a sliding door could damage or warp the grooves, which will affect the movement of the door. It’s often said that doing so is the equivalent of “stepping on the head of the host”, meaning you’re not only disrespecting them, but also hurting them.

Whatever the reason, it’s best to avoid stepping on the grooves of a sliding door, lest you offend your gracious hosts and do damage to their house. And by the way, it’s also considered rude to step on the borders of tatami mats, because in older times they used to have family crests embroidered into them, so it was seen as disrespectful. That, and, if you step on the edge you’re more likely to damage it, or push the edges downwards, which could make it easy to trip.

Tatami rooms are becoming less and less popular in Japanese homes, since they’re expensive, hard to maintain, and not very durable, so foreigners may never have to worry about it. But if you should enter a washitsu in a temple, tea ceremony school, ryokan, or other place of traditional Japanese culture, be mindful of these two simple rules and you should get along great with your hosts!

Source: Japaaan
Top image: Pakutaso
Insert images: Pakutaso (1, 2, 3, 4)
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