Early 80s Teapot from the famous Yixing Factory Number One with original box and sticker.

The teapot was not used and has been preserved in its original form with a full set.
Under the lid there is a stamp with the number "1", the origin of the numbers is unknown but most likely it is a batch or brigade number.
Purple clay is great for factory-made shu pu-erhs, as well as wet and dry-aged shu pu-erhs, wet-aged sheng, and teas that may seem too harsh such as young shen. It also rounds out green teas and light oolongs.