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Central Plains War During the
Central Plains War, Shi continued to serve under Feng. Following a series of defeats in May 1930, including the , and , Shi's secretary Liu Yidan arrived in Wuhan bearing a letter for
He Yingqin, in which he agreed to side with the
KMT government along with Han Fuju and all the soldiers under their command, totalling a third of all of Feng's forces. Shi had been incentivised by He's promise of generous concessions to generals under Feng willing to defect. It was this substantial loss that greatly contributed to Feng announcing his "retirement" and following flight to
Taiyuan with Yan Xishan. On 1 June, Shi received a reward of five million yuan and was named commander-in-chief of the 13th Route of the Anti-Rebel Army in an impromptu ceremony in Xuchang through Chiang's emissary . Despite this, Shi would still covertly assist the remainder of the anti-Chiang forces under
Sun Dianying in the
Battle of Eastern Henan, capturing Caozhuang Village with plans to kidnap Chiang from his command post at nearby , but the assigned troops failed to complete the 30-mile trek due to rain.
Conflict with Zhang Xueliang In early 1931, while in
Shenyang, Shi initiated contact with fellow warlord
Zhang Xueliang, who had similarly split off from Feng to work with the KMT, and offered to enter an alliance with him, to which Zhang agreed, giving Shi a monthly 600,000
yuan salary, with 200,000 yuan up front as a sign of goodwill. Shi then formed a military force headquartered in
Xingtai, composed of tens of thousands of former soldiers under Feng Yuxiang and Yan Xishan and used them to occupy the
Pinghan railway, having heard of Zhang's plans to do so. In May 1931, Shi began working with
Wang Jingwei, who had also joined forces with Li Rongzen, Chen Jitang and Liu Guitang, promising Shi a position in the anti-Chiang government being established by the
Western Hills Group led by
Hu Hanmin in
Guangzhou, also appointing commander-in-chief of the 5th Army Group and giving him 500,000 yuan.
Assassination of Zhang Zongchang In September 1932, Shi was suspected of having taken part in the killing of warlord
Zhang Zongchang, who had been a personal friend of his, in cooperation with his former allies Feng Yuxiang and Han Fuju, who had by then become military governor of Shandong. The day before Zhang's assassination, on 2 September 1932, Shi hosted a banquet in Han's name for Zhang to discuss a possible military operation to fight the Japanese, who had
invaded Manchuria the previous year. Shi expressed great interest in the revolver Zhang carried with him and received the same gun as a present by the end of the festivities. The event was later alleged to have been a ploy intended to get Zhang drunk and disarm him before he left the province to depart for Beijing by ways of Jinan's train station, where Zhang would be shot to death by , the vengeful adoptive son of , a general under Feng and one of his brothers-in-law, who was killed by Zhang during the
Warlord Era.
Early Japanese Collaboration In October 1932, Shi left Jinan for the
Japanese concession in Tianjin to attend clandestine meetings with Japanese general
Kenji Doihara and collaborator
Yin Rugeng, who had been providing him with local real estate for his cooperation. He also again associated with Liu Guitang, who was made an officer of the
Manchukuo Imperial Army and had begun recruiting former warlords for Japan. Chiang Kai-shek was aware of this betrayal and ordered Beijing station commander to arrange Shi's assassination, who in-turn tasked agent Wang Wen with going to Tianjin. Wang bribed Shi's camp assistant Xian Hongxia to have a chef poison a
hot pot Shi would eat with his third wife while she was on visit. The plan failed because Shi recognized the chef's anxious demeanour while serving and forced him at gunpoint to confess to the plot. Xian was arrested when she tried to grab Shi's pistol and handed over to Japanese authorities as an "agent of Nanjing", but Shi ultimately never learnt who ordered the attempt on his life. Shi briefly scaled back his dealings with Japan following the assassination of fellow warlord and collaborator
Zhang Jingyao on 7 May 1933. That same month, following the
Tanggu Truce, Shi was assigned Jibei (Northern Hebei) Security Command of the National Government by the Japanese occupation. Throughout 1934, during the late stages of the
Pacification of Manchukuo, he and Liu Guitang acted as agitators for the Japanese concession, conducting bandit operations and organising public unrest against ROC security forces within civilian zones in
Yutian,
Zunhua, and other areas bordering Tianjin from their headquarters in
Qinghe (now a
subdistrict of Beijing). This ended on 3 August 1935, when Liu was critically injured in an assassination attempt in
Luanzhou and temporarily put out of commission. The perpetrator, Li Zhenhua, claimed to have been acting on behalf of Shi and his inner circle, but Japanese officials heading the investigation instead blamed Tao Shaoming, who briefly held the executive office of supervisor and special delegate to the
Manchukuo buffer zone before being ousted after refusing offers to become a collaborator. Tao was remanded into custody for two weeks, but let go after his release was negotiated due lack of evidence. In December 1935, Shi sought a government job from his old brother-in-arms Song Zheyuan, who was now Governor of Chahar Province. By this point, Song held a great deal of disdain for Shi, knowing full-well of Shi's repeated betrayals, but due to outside pressure from the Japanese, who held control over his
governance, Song was convinced to make him the commander of the 181st Division, supposedly composed of former bandits under Feng Shoupeng in Hebei, to stop his persistent requests and keep him away from the Japanese forces he would likely be colluding with otherwise. Eventually, when the battalion was split into three regiments, Shi was reunited with Gao, who gained control of one of the other regiments along with Song. In early July 1936, Shi moved from the Japanese concession to the
British concession in Tianjin, following another assassination attempt on Liu Guitang on 20 June. == Second Sino-Japanese War ==