When I was in the Southern part of China, I noticed that he people looks basically like our Singaporean Chinese. I do noticed that the Northern Chinese who grow up in Northern China tends to have rosy checks even as adults living in the Southern part of china.

For those who have experience winter, you will know that it is very cold outside, but when the sun shines on you when you are inside a car, you can get sunburn.

I think, it is the same with ranchu. The UV rays and not the Infra- red rays.