Katorisenko is an old fashioned mosquito repellent commonly used in Japan during the summer months.
It is also known as a “mosquito coil” in English speaking countries.
The main ingredient is pyrethroid, which is taken from a flower called, Tanacetum cinerariifolium.
After you set flame to the edge of the coil, it begins emitting smoke.
It is this smoke which prevents the mosquitoes from coming.