Internal conflict among the nationalists (April–August 1927) As part of the First United Front, many members of the Chinese Communist Party had joined the KMT, and they exerted significant influence over its left-wing faction.
Mikhail Borodin, the official liaison between the KMT and the Soviet government in Moscow, had spent years cultivating this alliance, while covertly encouraging CCP expansion. This Soviet-backed leftist wing of the KMT came to dominate the nationalist government in Wuhan, which increasingly directed its ire at NRA commander-in-chief Chiang Kai-shek. On 1 April 1927, the Wuhan government, advised by Borodin, issued edicts stripping Chiang of his authority in foreign affairs, financial matters, and communications, and ordered that he leave his command post in Shanghai and go to the front. These orders had no effect, as Wuhan had almost no military authority. The government intended to send a small force to Nanjing with the aim of "disarming" Chiang, but put that plan on hold following
Wang Jingwei's return from exile in Europe. Wang, who had travelled back to China at the urging of members of the government, was greeted in Shanghai by Chiang, who offered a power-sharing deal. Wang said that he would consider the deal, and boarded a ship for Wuhan on 7 April. He arrived on the 10th, where he was eagerly greeted by the Wuhan leadership. Having heard from Wang about Chiang's offer, the government decided to turn its limited forces toward Beijing instead. Chiang, on the other hand, was already preparing for a purge of communists in Shanghai. Between 12 and 14April, hundreds of communists in Shanghai were arrested and killed on the orders of Chiang in a disturbance that came to be called the "
Shanghai massacre", effectively ending the alliance between the nationalists and the communists. Chiang engaged the
Green Gang underworld group to kill all trade unionists and communists within the city. The purge was condemned by the Wang Jingwei, now leader of the Wuhan government, formalising the split between the KMT leftists based in Wuhan and the KMT rightists, who subsequently established their own government in Nanjing. The precariousness of the NRA position in Nanjing was clear: at ceremonies held to commemorate the city's elevation to capital of China, warlord Zhang Zongchang's artillery bombarded the city's waterfront from across the Yangtze. With the Nanjing–Shanghai area under constant threat of attack from the NPA, a series of independent offensives was launched by NRA and NRA-aligned forces in May 1927.
Feng Yuxiang and his
Guominjun moved first, leaving their base in
Shaanxi to march on
Luoyang, in Henan. On 10 May 1927, the NRA First and Sixth armies crossed the Yangtze into Anhui, and on 16 May, Li Zongren, based in western Anhui, led the Seventh Army toward Hefei. Concurrently, the Wuhan government launched its own campaign in Henan province led by
Tang Shengzhi, who was appointed to serve as the Wuhan army's commander-in-chief. Aided by the defection of remnants of Wu Peifu's forces, Tang advanced to fight the forces of the "Young Marshal"
Zhang Xueliang, Zhang Zuolin's son and heir, pushing them back to a river at
Yancheng. By 20 May, Li had captured Bengbu, whilst Chiang unleashed a four-pronged attack through Jiangsu, toward the warlord power base in Shandong. He Yingqin led the NRA First Army across the Yangtze at
Zhenjiang, and moved to capture
Haizhou. On 28 May, Li took
Suzhou, while the
Guominjun took Luoyang, forcing Zhang Zongchang to withdraw his forces to Shandong, and Zhang Xueliang to fall back north of the
Yellow River. Following Xueliang's retreat, Feng Yuxiang moved east from Luoyang to
Zhengzhou. Finally, on 2 June 1927, the NRA captured the vital railway junction of
Xuzhou. With both the
Longhai and
Beijing–Hankou railways under NRA or
Guominjun control, Feng came into direct contact with the Wuhan and Nanjing factional governments, who both sought his aid. He met with Wang Jingwei and Tang Shengzhi at Zhengzhou on 10–11 June, then travelled to
Xuzhou to meet with Chiang Kai-shek on 19 June. On the next day, Feng
announced that he would align with the Nanjing faction and purge communists from the areas under his control, crippling the Wuhan government's plan to push north, upon which Tang returned to Wuhan with his troops. Whilst Chiang intended to push into Shandong, he was thwarted by the arrival of the Japanese
Kwantung Army during the course of June, who were ostensibly deployed to protect Japanese citizens in
Qingdao. Around this time, Wu Peifu retreated with his remaining forces into Sichuan, where he announced his retirement. On 5 July, NPA general Chen Yi-yen defected to the NRA, but failed to convince his 10,000 soldiers at Qingdao to do likewise. At Wuhan, Tang Shengzhi began to mobilise his troops for an attack on the Nanjing government. Aware of this threat, Chiang recalled troops from the Shandong border in an effort to block Tang. In turn, the NPA launched an attack on Chiang in early July, reclaiming much of the territory they had lost. By 24 July 1927, the NPA had retaken Xuzhou. In the face of mounting losses inflicted by the warlords, the Wuhan and Nanjing factions began reconciliation talks. The Wuhan government
purged communists from its ranks and expelled Soviet advisors, facilitating a rapprochement between the two factions, but also sparking the communist
Nanchang uprising, which weakened its authority. In the meantime, however, the NPA counter-offensive continued, reaching Bengbu on 9 August, and forcing Chiang to withdraw his troops south of the Yangtze. In return for his co-operation, Wang Jingwei demanded that Chiang resign from his post of commander-in-chief, and relinquish all political titles. Accordingly, Chiang resigned from his post on 12 August 1927, though this did not immediately reunify the Wuhan and Nanjing factions.
Without Chiang Kai-shek (August 1927–January 1928) warlord
Yan Xishan started to fight the NPA in October 1927, strengthening the
KMT military position As the two sides attempted to reconcile their political differences, Sun Chuanfang's forces continued to bombard Nanjing from across the Yangtze. Sensing the NRA's continual disarray, Sun moved to try and recapture Shanghai, contrary to the wishes of NPA leader Zhang Zuolin. On 25 August, NPA landing parties were dispatched to cross the Yangtze at Longtan, near Nanjing. In the early morning of 26 August 1927, thousands of Sun's troops crossed the river, rallying at the Longtan station of the Shanghai–Nanjing railway. Li Zongren's NRA Seventh Army managed to drive the NPA away from the railway briefly, but thousands more of Sun's troops, including
White Russian mercenary units, crossed the river the next day and retook the station, cutting off contact between Nanjing and Shanghai. The reeling NRA sent missives to all factions within the revolutionary movement, calling for unity in the face of Sun's advancing troops. Accordingly, in an attempt to put pressure on Sun, Feng Yuxiang and his
Guominjun launched an attack into Shandong on 28 August, while Wuhan sent its troops north, trying to flank Sun, and He Yingqin approached from Shanghai. With its forces encircled, and unable to continue to move troops across the river, the NPA was forced to abandon Longtan railway station on 30 August. In a desperate attempt at resistance, Sun rallied his 40,000 remaining troops and launched a counter-offensive on 31 August, only to be crushed in a hard-fought battle that left more than 10,000 of those troops dead. While Sun was able to escape to Shandong, his surviving troops were forced to surrender to the NRA. With victory in hand, reconciliation talks restarted on 7 September, and on 15 September, the Wuhan government was dissolved, with a new joint government established in Nanjing, under the leadership of
Guangxi clique generals. Wang Jingwei refused to join the new government, as did Tang Shengzi, who became an independent warlord in his own right, controlling Hubei, Hunan, Jiangxi, and parts of Anhui. On the other hand,
Shanxi warlord Yan Xishan, theretofore independent, aligned his province with the Nanjing government, adding 100,000 troops to NRA ranks and increasing the pressure on Zhang Zuolin. In the subsequent fighting, neither the Shanxi nor Fengtian forces managed to gain the upper hand. Yan's troops successfully withstood a massive siege at
Zhuozhou, but went on to suffer a heavy defeat at
Baoding on 15 October 1927. The threat from Tang's forces, however, prejudiced any further northward advance by the NRA, and so in October, it moved to quash his rebellion. Tang was defeated in early November, and left for exile in Japan shortly afterwards. With Tang dealt with, the push north resumed, reaching Bengbu by 9 November. Continuing their advance, the NRA and Feng Yuxiang's
Guominjun moved toward
Xuzhou. The NPA attempted a counter-offensive on 12 December, led by
armoured trains, but was quickly forced back by the combined NRA and
Guominjun forces, which took Xuzhou on 16 December. The NPA retreated once more to Shandong. Meanwhile, in Guangzhou,
a communist uprising broke out on 11 December 1927. The violent rebellion was quickly put down, and on 13 December, Chiang Kai-shek called for the ending of all remaining relations with the Soviet Union. The Nanjing government agreed, and also aired its suspicions over the allegiances of Wang Jingwei, who had been based in Guangzhou after the end of the Wuhan government. Wang left for exile in France on 17 December, paving the way for Chiang's return as commander-in-chief. With the military success of Chiang's
Whampoa troops, the various KMT factions agreed to recognise the legitimacy of Chiang's leadership. Consequently, Chiang was officially invited to resume command of the NRA on 1 January 1928.
Regrouping and Jinan incident (January–May 1928) With the frigid winter of northern China prohibiting any further advance, Chiang used the months following his reappointment to consolidate his control and restore the integrity of the Nanjing administration. On 18 February 1928, Chiang was granted the title "Commander-in-Chief of the Northern Expeditionary Forces", whilst He Yingqin was made NRA chief-of-staff. The NRA was reorganised into four "collective armies". The First Collective Army was made up largely of the original NRA forces from Guangzhou, now based in the Nanjing–Shanghai area. The Second Collective Army consisted of Feng's
Guominjun, the Third of Yan's Shanxi forces, and the Fourth of Li Zongren's Guangxi clique army. By this point, the NRA was made up of one million soldiers, most of them part of ex-warlord armies. Preparing for a resumption of the expedition in March, Chiang ordered his foreign ministry to negotiate with the Japanese, in order to try to prevent their further intervention in Shandong. By 1 April 1928, Feng's NRA Second Collective Army (
Guominjun) and Yan's NRA Third Collective Army had started to fight the NPA on the Henan–Shandong border and along the Beijing–
Suiyuan railway. The resumption of the Northern Expedition was officially launched by Chiang Kai-shek on 7 April. With the NPA line softened by Feng and Yan's attacks, the NRA First Collective Army rushed into Shandong along the
Tianjin–Pukou railway, capturing
Tengzhou by 16 April. Meanwhile, Feng's forces advanced into Shandong from the west, capturing
Jiaxiang on the 15th. Sun Chuanfang decided to attempt a two-pronged counter-offensive against the NRA First and Second armies, managing to push the First back to the
Longhai railway. His attack against the Second Army failed, and by the 21st, the combined NRA had forced him to withdraw from
Jining to the provincial capital
Jinan. According to an American account of Sun's retreat, the "great majority of the troops in this retreat literally walked the soles off their shoes, and this, combined with the scarcity of food and total lack of shelter left the vast horde without any idea of further resistance". The Japanese, meanwhile, having heard of Sun's defeat, began to move Kwantung Army troops by train from Qingdao to Jinan. While the NRA Second Collective Army advanced northeast to Jinan along the southern bank of the Yellow River, the First Collective Army diverged east from the Tianjin–Pukou railway at
Tai'an, crossing the
Taishan mountains to attack Jinan from the west via the
Qingdao–Jinan railway. This strategy was successful, and by 29 April 1928, the NRA had nearly encircled Jinan. The beleaguered NPA retreated to the north bank of the Yellow River, amidst looting and outbreaks of violence. At this point, there were already 3,000 Japanese troops in Jinan, guarding the 2,000 Japanese civilians in the city. On the next day, NRA troops entered Jinan. Chiang Kai-shek arrived on 2 May 1928, and attempted to negotiate a Japanese withdrawal from Jinan, issuing safety guarantees for Japanese civilians to local Kwantung Army commander
Hikosuke Fukuda. Fukuda agreed, and his troops prepared to leave that night. Early the next morning, conflict broke out between the Chinese and Japanese troops, starting what came to be called the "
Jinan incident". What began as a minor armed altercation escalated on 8 May into a full-scale Japanese attack on the city. During the course of the incident, the Japanese killed KMT foreign affairs commissioner
Cai Gongshi, several diplomats, and about five thousand Chinese civilians.
Final offensive and capture of Beijing (May–December 1928) Deciding to avoid further confrontation with the Japanese, the NRA First Army continued its march north by going around Jinan to capture
Dezhou on 13 May 1928, while the NRA Second Army moved north along the Beijing–Hankou railway. Meanwhile, Yan Xishan's NRA Third Army proceeded toward Beijing from its base in Shanxi. The Second and Third armies met at Baoding on the
North China Plain. While the Second Army besieged that city, the Third Army went north toward
Zhangjiakou, gateway to Beijing. On 17 May, however, the forces of Zhang Zuolin launched a 200,000-man counter-offensive, forcing the First Army back and the Second Army south of Baoding. As fighting grew closer to Beijing, the Japanese sent a communique to both the NRA and Zhang, warning that any fighting in Manchuria would result in a Japanese intervention in that region. Zhang, weary of KMT propaganda that linked him with the Japanese massacre at Jinan, responded that he would "not recognize Japan's interest in Manchuria", compromising his position. With his troops demoralised, the momentum of the NPA counter-offensive fizzled out by 25 May, and the Third Army was able to capture
Zhangjiakou on that day, and
Nankou Pass on the next. With pressure growing on his vital railway links, Zhang gradually began to withdraw his troops from the North China Plain on 30 May. In the face of the NRA onslaught, and under pressure from the Japanese, Zhang decided to evacuate to Manchuria by train, leaving with his staff on 3 June. Early the next morning, on 4 June 1928, a bomb planted by the Japanese Kwantung Army exploded under the train, killing Zhang in the so-called "
Huanggutun incident". His remaining forces, even further demoralised, crumpled under the pressure of the NRA advance. Sun Chuanfang unleashed the final blow to the NPA when he withdrew his troops from the defensive line and fled to
Japanese-controlled Dairen on 4 June. On 6 June, the NRA Third Collective Army marched into Beijing, ending the Beiyang government. The other NRA armies would arrive in the Beijing area over the next few days. Zhang Zongchang subordinate
Xu Yuanquan subsequently surrendered Tianjin to the NRA First Collective Army on 11 June. Zhang Xueliang succeeded Zhang Zuolin as leader of the Fengtian clique, and decided to end the war and to co-operate with the nationalists. The Shandong–Zhili Army led by Zhang Zongchang and
Chu Yupu refused to surrender, and despite the defeats it had suffered still numbered about 60,000–70,000 soldiers, as well as at least three armoured trains manned by White Russian mercenaries under General
Konstantin Nechaev. As Zhang Xueliang had sided with the nationalists, Zhang Zongchang declared war on the Fengtian clique. Supported by Japan, the Shandong–Zhili Army moved from its base at
Tangshan on 2 August 1928, crossed the
Luan River, and invaded Manchuria. After six days of fighting, however, the defiant warlord army was trapped by KMT and Zhang Xueliang–aligned forces; many of Zhang Zongchang's troops (including the White Russian mercenaries) defected or deserted, and those who refused to surrender were killed. Zhang Xueliang officially declared his allegiance to the nationalist government in Nanjing on 29December 1928, marking the formal end of the Northern Expedition, and the
reunification of China. == Aftermath ==