My Mother calls this piece of china her 'Cocoa Jug', but after some digging, I discovered that it is actually known as a Nippon 'Chocolate Pot'. Most of the examples are valued at approximately $400 and upwards to $1200+ if it comes with the tiny cups and saucers.
My next surprise was that Nippon is not actually a company. Nippon generally refers to Japanese wares made during the period from 1891 to 1921, although the Nippon mark was also used to a limited extent on later wares accompanied by "Japan". Nippon, meaning Japan, identified the country of origin to comply with American importation restrictions. After 1921 "Japan" was the acceptable alternative. The term does not imply a specific type of product and may be found on items other than porcelain.
Regardless of it's history or current value, I treasure the stories my Mom tells me about drinking sweet hot chocolate (the real kind) by a crackling fire when she was 2 or 3 years old. I have an old photograph of her sipping the warm treat. I just adore how the gold (real) has worn away off the ornate handle from all those loving hands pouring cocoa.