The origin of the breed we call Croad Langshan goes back to times immemorial.
According to Chinese websites    it was the local breed of the Rudong and Nantong area on the northern bank of the great Yangtze River, about 100km from Shanghai.
The breed was originally called "Big Chicken Cha" [岔河大鸡] or "Black Chicken Matang"[马塘黑鸡], after two towns in the Rudong area, Chahe and Matang.
Today it is referred to as Langshan Ji [狼山鸡].
Besides Chahe and Matang Juegangzhen, Bingchazhen, Fenglizhen, Shuangdianzhen, Shiganagzhen, Tonzhu District and Nantong are mentioned as having Langshans; an area of roughly 40 x 60 km.
This region with its humid subtropical climate, well-drained, fertile soils and irrigation channels has long been densely populated with small family farms growing corn, barley, rice, supplemented with fish and shellfish. Recent excavations show that it has been settled at least 8000 years ago.
Chickens have always been common on these farms, foraging in the fields and along the irrigation channels. Every family bred their own and little exchange between farms took place.
There seem have been many different strains with heavier birds centred around Chahe and Matang (cock 4.5-5kg, hen 3-3.5kg) and a smaller strain around Bingchazhen (cock 3-3.5kg , hen 2kg).
By far the most common colour is black, but there are some white, and more rarely, buff birds. A variety of comb types and different degrees of foot feathering are mentioned.
As in other countries modern times have seen a decline in original local breeds.
One source  states their number as 5000 for the year 2002.
And a website which no longer exists  said (2005):
Today with the introduction of overseas species, Lang Shan Ji is decreasing in numbers and only 2000-3000 exist.
-  China Academy of Agricultural Sciences Beijing Institute of Animal Husbandry and Veterinary Information Center, Beijing, China. (This link no longer works)
-  GLULU Halal Food Culture, Address: Ningxia, Yinchuan 750001 Tel: 13519209235 13430211135 E-mail: firstname.lastname@example.org (This link no longer works)
-  Baidu Encyclopaedia (http://baike.baidu.com/)
-  Huazhong Agricultural University, Wuhan, China
-  “Name that chicken” in Beijing Today, February 11, 2005 By Zhao Hongyi