This is actually an inset map on the back
of a large colour map called 東亞現勢大地圖 published by 大日本雄辯會講談社 in Tokyo, January 1938. It shows the situation as of November 1937,
just one month before Nanking was occupied.
This digital image was taken from a Blackberry mobile phone, with English title and map orientation added.
Also added is the name 明故宮 (palace of the Ming dynasty) on its site to the west of 中山門, based on a Chinese city map of 1936.