Asian sizing (Japan, Korea, China) is generally cut 1–2 US sizes smaller. An Asian Medium fits like a US X-Small.
Tops: Asian L ≈ US S, Asian XL ≈ US M, Asian XXL ≈ US L.
Pants: Asian sizes use cm waist measurement (28, 29, 30…). Same numbers as US inch waists, but the rise and leg are usually narrower.
Aliexpress, Yesstyle, and Korean brands all use Asian sizing by default. Always order at least one size up.
Shoes: Asian sizes use cm foot length directly. 25cm = US 7 men's / US 8 women's. This is more accurate than letter sizes.