Because the ancients were stupid.

Are you kidding? If the ancients were really so stupid, can we in Greater China still be passed down to this day?

This thing is called a half arm and is worn in public. The sleeves that look very long are very thin, which is equivalent to today's sunshade armholes.

What about private occasions? Then who cares what you wear?

To put it bluntly, this is a layer of gauze inside and outside.

Well, after all, she is a married woman. Wear it in broad daylight.

Song and Ming dynasties looked much more conservative-but keeping warm is better than being conservative. The climate has been getting cold during the Song and Ming Dynasties, and it completely turned into the "Little Ice Age" at the end of the Ming Dynasty. Only fools wear short sleeves in cold weather!

If there is any relationship between warmth and conservatism, it must be the need to keep warm that leads to conservatism, and it is never designed to make people wear so hot because of conservatism.