A senior high school student holds a textbook about the Nanjing Massacre in Nanjing, capital of east China's Jiangsu Province, Dec. 1, 2014. The textbook named "Warning and Thinking" is officially issued here on Monday. Besides it, the primary school edition, called "Memory of Blood and Fire, and the junior middle school edition, "Historical Truth," were also published. In February of this year, China's top legislature designated Dec. 13 as the National Memorial Day for Nanjing Massacre Victims to mourn the Nanjing Massacre victims and all of those killed by Japanese invaders. To help students better understand the massacre, in which more than 300,000 people were killed in Nanjing in late 1937 and early 1938, experts from the educational bureau of Nanjing, the Memorial Hall of the Victims in Nanjing Massacre by Japanese Invaders, as well as a Nanjing publishing media group compiled these three textbooks. (Xinhua/Sun Can)