Analysis of information sources in references of the Wikipedia article "장진호 전투" in Korean language version.
The Japanese built the reservoir and named it Choshin. The proper Korean name is Changjin. The most popular alternative spelling is the one given here. It was on most of the tactical maps of the time.
Fighting around the Choshin Reservoir*... *This was the Japanese name for the reservoir. American also rendered it as Chosin or Chosen. The proper Korean name is Changjin.