What is their purpose in doing so?

If you’ve ever wandered through a quiet residential neighborhood in Japan, you might’ve spotted something a bit puzzling—rows of clear plastic water bottles lined up neatly along fences, garden edges, or the base of walls. At first glance, they might seem like forgotten recycling or leftover items from a picnic. But these bottles are actually placed there with intention. They’re called nekoyoke, which translates to “cat repellents.”

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What’s the Purpose of These Bottles?

Despite cats being beloved pets and cultural icons in Japan, stray cats can sometimes cause trouble. They might damage garden beds, leave waste behind, or pose health concerns due to disease transmission. As a preventive measure, some residents line their property with water-filled bottles in an attempt to discourage stray cats from entering or marking their territory.

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Why Do People Think This Works?

To outsiders, this habit might appear unusual, but it’s surprisingly common across many Japanese towns and cities. The belief is that when sunlight or artificial light hits the water in the bottles, it creates glimmers and flashes. These sudden light reflections are thought to startle or confuse cats, discouraging them from approaching.

Additionally, some believe the distorted reflections or the way light refracts through the water may interfere with a cat’s depth perception, making the area seem uncertain or uninviting to them.

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Where Did This Tradition Originate?

Interestingly, the idea didn’t originate in Japan. It’s believed to have started in Western countries during the 1980s—though originally, the goal was to deter dogs rather than cats. When the concept made its way to Japan, it was adapted to address feline intrusions in home gardens and walkways.

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Does It Really Keep Cats Away?

This is where things become less clear. Scientific studies have not found strong evidence that water bottles are an effective way to deter cats, especially in low-light conditions where reflections are minimal. Despite this, many continue the practice—out of tradition, optimism, or simply because it’s a harmless effort that might help.

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More Than Just a Repellent

Even if their effectiveness is debatable, these water bottles are non-toxic and don’t pose any harm to animals. Over time, they’ve evolved from being just a DIY deterrent to a fascinating cultural feature. For many, they represent more than their practical purpose—they showcase Japanese values like creativity, subtle problem-solving, and attention to aesthetics.

Whether or not they succeed in keeping cats at bay, these bottles contribute to the quiet charm of Japanese streets and leave a lasting impression on visitors and locals alike.

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Know Any Other Unique Problem-Solving Traditions?
There are countless cultural solutions to everyday issues around the world, many of which are just as inventive. Do you know of any others that are used to tackle common problems in unexpected ways?