Why is the mosquito coil a spiral? What was the wife's brilliant idea...?
On a summer evening, the scent of mosquito coils drifts in from somewhere. Whenever I smell that fragrance, I am instantly reminded of the veranda of my childhood home. By the way, have you ever wondered why that unique "spiral" shape is the way it is? In fact, hidden within it is the wisdom of a married couple and the grand story of a mandarin orange farmer. Today, I will tell you the full story of its surprising origin.
Mosquito coils were originally "stick-shaped"
It might be surprising, but mosquito coils were not spirals from the beginning. When they were first created, they were "stick-shaped," much like the incense sticks offered at a Buddhist altar.
They were invented by a man named Eiichiro Ueyama from Wakayama. In 1890 (Meiji 23), he mixed the powder of a chrysanthemum called "pyrethrum," which has insect-repelling properties, with mandarin orange peel powder and other ingredients to create a stick-shaped incense. This is considered the world's first mosquito coil.
However, this stick type had a weakness. It was only about 20 centimeters long, and it only burned for about 40 minutes. That is not enough to sleep soundly through the night, is it?
▼ Sources
・The Invention of the Mosquito Coil (Eiichiro Ueyama) (National Archives of Japan)
https://www.archives.go.jp/exhibition/digital/hatsumei/contents/42.html
・Mosquito coil (Wikipedia)
https://ja.wikipedia.org/wiki/蚊取り線香
It was the wife's flash of inspiration that created the spiral
The person who solved the problem of the "short burning time" was, surprisingly, Eiichiro's wife, Yuki.
According to the anecdote, Yuki saw a snake coiled up in the garden and had a flash of inspiration: "If we use that shape, couldn't we make the incense longer?" While a straight stick takes up space, if you wind it into a spiral, you can fit a long piece of incense into a compact shape. It is a true shift in perspective.
I really love this story. A great invention used all over the world was born from a casual observation in daily life. And the fact that it was the wife, not the inventor himself, who came up with it—don't you think that's a wonderfully stylish story?
▼ Sources
・It was originally a stick!? The reason why mosquito coils became spiral-shaped (Mynavi News)
https://news.mynavi.jp/kikaku/20230626-kincho/
・Is the spiral clockwise or counter-clockwise? The history of the evolution of the mosquito coil's "spiral" (tenki.jp）
https://tenki.jp/suppl/marinahishinuma/2018/08/09/28329.html
Why was the spiral revolutionary?
The spiral shape had clear practical benefits.
One was that the burning time increased dramatically. By winding the incense into a long spiral, it evolved from the 40-minute stick to a length that lasts all night. This made it harder for mosquitoes to approach while you were sleeping. Another benefit was safety. With a stick, there is a risk of it falling over and causing a fire, but if you lay a spiral flat, it is unlikely to tip over. This spiral shape solved both the issues of length and safety at once.
Thus, in 1895 (Meiji 28), the spiral-shaped mosquito coil was born. It was the crystallization of the exquisite teamwork between Eiichiro and Yuki.
Also, people often discuss whether the spiral is "clockwise or counter-clockwise," but this seems to depend on the product and how it is placed, and there does not appear to be an absolute rule. It might be fun to check for yourself next time you use one.
▼ Sources
・Why is it a spiral? 5 secrets of mosquito coils (Weathernews)
https://weathernews.jp/s/topics/202107/160215/
Did it all start with a single mandarin orange farmer?
Finally, a little bit about the inventor, Eiichiro Ueyama himself. He was originally a farmer who was trying to export mandarin oranges and other goods overseas. It is said that everything began when he received pyrethrum seeds from abroad through those connections.
Since the Heian period, people had a custom called "kayaribi" (mosquito-repelling fire), where they would burn plants to keep insects away. Eiichiro combined that wisdom with the new material of pyrethrum, and then completed the shape with his wife's idea. This summer tradition was born from the overlap of ancient living wisdom and the ingenuity of a married couple. I was quite moved to learn that there is such a story behind a tool we use so casually.
▼ Sources
・Can you explain why mosquito coils became "spiral-shaped"? (PRESIDENT Online)
https://president.jp/articles/-/56086
Summary for today
1. Mosquito coils were initially "stick-shaped" and only burned for about 40 minutes.
2. The spiral was created by the inventor's wife, Yuki. It is said to have been inspired by a coiled snake.
3. The spiral was a brilliant invention that achieved both "long burning time" and "safety without tipping over."
In this blog, I will slowly dig deep into the origins of Japanese culture that exists close to our daily lives. Next time, I plan to cover "Why is uchimizu (sprinkling water) cooling?" Please follow if you are interested.
Editor's note: The more we use things that we take for granted, the more endearing they become when we learn their origins. This summer, every time I light a mosquito coil, I think I will remember that couple.