The January 28 incident or Shanghai incident (January 28 – March 3, 1932) was a conflict between the Republic of China and the Empire of Japan. It took place in the Shanghai International Settlement which was under international control. Japanese army officers, defying higher authorities, had provoked anti-Japanese demonstrations in the International Settlement following the Japanese invasion of Manchuria. The Japanese government sent a sect of militant ultranationalist Japanese Buddhist priests belonging to the Nichiren sect to Shanghai. The monks shouted anti-Chinese, pro-Japanese nationalist slogans in Shanghai, promoting Japanese rule over East Asia. In response, a Chinese mob formed killing one monk and injuring two. In response, the Japanese in Shanghai rioted and burned down a factory, killing two Chinese. Heavy fighting broke out, and China appealed with no success to the League of Nations. A truce was finally reached on May 5, calling for Japanese military withdrawal, and an end to Chinese boycotts of Japanese products.
Internationally, the episode intensified opposition to Japan's aggression in Asia. The episode helped undermine civilian rule in Tokyo; Prime Minister Inukai Tsuyoshi was assassinated on May 15, 1932.
In Chinese literature it is known as the January 28 incident (), while in Western sources it is often called the Shanghai War of 1932 or the Shanghai incident. In Japan it is known as the First Shanghai Incident (第一次上海事変), alluding to the Second Shanghai Incident, which is the Japanese name for the Battle of Shanghai that occurred during the opening stages of the Second Sino-Japanese War in 1937.
After the Mukden Incident, Japan had acquired control over Manchuria and would eventually establish the puppet government of Manchukuo. However, the Japanese military planned to increase Japanese influence further, especially into Shanghai, where Japan, along with the various western powers, had extraterritorial rights.