I found this while cleaning the gutters before the rainy season, and thought it was a shiso leaf, but it was actually a perilla leaf!
I ate it with chilled somen noodles and cold tofu as a side dish, but it didn't have much of a fragrance and I now understand why the texture was different.
Perilla leaves are shallowly incised, rounded, and red on the underside.
Perilla leaves had been shipped to the hometown market, and I realized that what I had replanted was not shiso but perilla, so I was glad to have the mystery solved.
When I searched, I found that shiso and perilla cross-breed well, and that they should be planted at least 200m apart.
Seeing is believing, so thank you.