China’s war against Japan eventually merged into the greater world war.  Particularly after the attack on Pearl Harbor, Japan became a central concern to the Allies, especially the United States. 

Soon after the Japanese began their war against China, it had planned to pacify and consolidate the territory she had gained in China.  However, largely unsuccessful, by 1942, she had bigger issues with the Allies’ efforts against her in the Pacific. 

That did not deter her from successfully launching and completing her largest military campaign in China.  In the spring of 1944, Japan began Operation Ichigo.  A massive and impressive military offensive to link northern Asia and southern Asia and to rid China of the American airfields.