Chinese Black Pears

When I was at school in Worcester the garden there grew an old variety of fruit tree, the Worcester Black Pear. Once a year the gardener picked them and they were stewed for dessert. Their skins were dark but not black and the flesh pale, but stewed to a pink-red sunset in the bowl.
So, I was intrigued to find these black skinned pears sitting out overnight in temperatures down to -15 with a rime of frost on them. The flesh is cream and firm inside, not brown and bletted as are medlars. They are a speciality of the Northern street markets and a good local buy. I think they are called Dongbei pears