There is no such breed as an “imperial” or “teacup” Shih Tzu. These are simply marketing terms used by unscrupulous breeders use to indicate a very small or large Shih Tzu.
There isn’t much mention of the dogs in documents from the 1700s to the early 1900s, but many pieces of art from that period depict small, shaggy, happy dogs.
Affection is their dominant characteristic, and your lap is their favorite destination. They’re happiest when they’re with their family, giving and receiving attention.