Editing Second Sino-Japanese War (section)

===1929 Sino-Soviet war===
{{Main|Sino-Soviet conflict (1929)}}

The July–November 1929 conflict over the [[Chinese Eastern Railroad]] (CER) further increased the tensions in the Northeast that led to the [[Mukden Incident]] and eventually the Second Sino-Japanese War. The Soviet [[Red Army]] victory over Xueliang's forces not only reasserted Soviet control over the CER in Manchuria but revealed Chinese military weaknesses that Japanese Kwantung Army officers were quick to note.<ref>Michael M. Walker, ''The 1929 Sino-Soviet War: The War Nobody Knew'' (Lawrence: University Press of Kansas, 2017), p. 290.</ref>

The Soviet Red Army performance also stunned the Japanese. Manchuria was central to Japan's East Asia policy. Both the 1921 and 1927 Imperial Eastern Region Conferences reconfirmed Japan's commitment to be the dominant power in the Northeast. The 1929 Red Army victory shook that policy to the core and reopened the Manchurian problem. By 1930, the Kwantung Army realized they faced a Red Army that was only growing stronger. The time to act was drawing near and Japanese plans to conquer the Northeast were accelerated.<ref>Michael M. Walker, ''The 1929 Sino-Soviet War: The War Nobody Knew'' (Lawrence: University Press of Kansas, 2017), pp. 290–291.</ref>