What is the Huanggutun incident?

1928, 14 In June, the Japanese Kwantung Army shot and killed Zhang, the leader of the Feng warlord, at Huanggutun Railway Station near Shenyang. Zhang was the leader of the Fengzhi warlord supported by Japanese imperialism, became the "Northeast King" who ruled the three northeastern provinces, and expanded to Shanhaiguan many times. 1in June, 927, an Guo Jun government was established in Beijing, becoming the last ruler of Beiyang government. At this time, Zhang tried to use Britain and the United States to contain Japan, such as introducing American capital in the northeast and asking the United States to build railways such as Datong (Dahushan to Tongliao) and Shenhai (Shenyang to Hailong) and Huludao port. However, Japan's demands to build Ji-Lin-Hui (Huining, North Korea) railway, open mines and set up factories for immigrants, and prevent China from building a port in Huludao were not complied with, which caused Japan's dissatisfaction. After Tanaka came to power on April 1927, he asked Zhang Suo for railway rights and forced Zhang to solve all "unsolved cases", which aroused the anti-Japanese anger of the northeast people. On September 4th, 20,000 people demonstrated in Shenyang, shouting "Down with Tanaka Cabinet". Guan Dongjun concluded that this was caused by instigating Zhang, and he hated his guts. 1928 In May, the Northern Expedition led by Chiang Kai-shek defeated the army, and Zhang was ready to return to Shenyang by train. Tetsutaro Muraoka, commander of Kwantung Army, intends to send someone to assassinate Zhang, but this action is not easy to cover up his guilt. So Colonel Kawamoto, a senior staff officer, planned to blow up the car and mobilized engineers to bury explosives at the intersection of Nanman Road and Jingfeng Road at Zhanghuanggutun Station. At 5: 30 am on June 4, Zhang's train arrived at Huanggutun Station and was attacked by a bomb. Wu, governor of Heilongjiang, died on the spot and Zhang was seriously injured. He was rushed back to Shenyang and died at 9: 30 in the morning. At that time, Japan falsely accused the "southern plainclothes players" in order to cover up the truth. 1in July, 946, when the Japanese war criminals were tried by the "Far East International Tribunal" in Tokyo, Katsuya Okada, Minister of the Maeda Navy of Japan, testified in court and confessed that the bombing of Zhang was committed by the Kwantung Army. At this point, the truth came out.