The 'Battle of Nanking' was fought between Japanese and Chinese forces for control of Nanking, the capital of the Republic of China, in the 2^nd Sino-Japanese War (1/13 December 1937).

Following the outbreak of the 2^nd Sino-Japanese War between Japan and China on 7 July 1937, the Japanese initially sought to contain the fighting and attempted to negotiate a settlement. However, after the Japanese victory in the 'Battle of Shanghai', expansionists prevailed within the Japanese military and on 1 December a campaign to capture Nanking was authorised. The task of occupying Nanking was given to General Iwane Matsui, commander of the Central China Area Army, who believed that the capture of Nanking would force China to surrender and thus bring an end to the war. Chiang Kai-shek, the Chinese Nationalist leader, decided to defend the city and appointed General 1^st Rank Tang Shengzhi to command the Nanking Garrison Force, a hastily assembled army of local conscripts and the remnants of the Chinese units which had fought in Shanghai.

The Japanese troops advanced with great speed from Shanghai to Nanking, rapidly defeating pockets of Chinese resistance. By 10 December the Japanese had reached the Chinese forces' last line of defence, the Fukuo Line, behind which lay Nanking’s fortified walls. On 10 December Matsui ordered an all-out attack on Nanking, and after less than two days of intense fighting Chiang decided to abandon the city. Before fleeing, Tang ordered his men to attempt a concerted break-out through the Japanese siege, but by this time Nanking was largely surrounded and its defences were at the breaking point. Most of Tang’s formations and units collapsed, their soldiers often abandoning their weapons and uniforms in the streets in the hopes of hiding among the city’s civilian population.

Following the capture of the city Japanese massacred Chinese prisoners of war, murdered civilians, and committed acts of looting and rape in an event known as the Nanking Massacre. Although the military victory excited and emboldened the Japanese, the subsequent massacre tarnished their reputation in the eyes of the world. Contrary to Matsui’s expectations, China did not surrender and the 2^nd Sino-Japanese War continued for another eight years.

The conflict that became known as the 2^nd Sino-Japanese War had begun with the skirmish at the Marco Polo bridge, outside Peking, an incident which escalated rapidly into a full-scale war in northern China between the armies of Japan and China.The latter wished to avoid a decisive confrontation in the north, and therefore opened a second front by attacking Japanese units in Shanghai, which the Japanese had taken in January 1932, on the eastern coast of central China. The Japanese responded with the despatch of the Shanghai Expeditionary Army, under Matsui’s command, to expel the Chinese forces from Shanghai. Intense fighting in Shanghai forced the Japanese army’s general staff into a steady reinforcement of the Shanghai Expeditionary Army, and finally on 9 November an entirely new formation, the 10^th Army commanded by Lieutenant General Heisuke Yanagawa, was also landed at Hangzhou Bay, just to the south of Shanghai.

Although the arrival of the 10^th Army forced the Chinese army to retreat from Shanghai, the Japanese general staff had decided to adopt a policy of non-expansion of hostilities with the aim of ending the war. On 7 November, the de facto Japanese military leader, Lieutenant General Hayao Tada, the deputy chief-of-staff, ordered an 'operation restriction line' preventing the Japanese forces from leaving the area of Shanghai, or more specifically from passing to the west of the Chinese cities of Suzhou and Jiaxing. Nanking is 185 miles (300 km) to the west of Shanghai.

However, there was a major division of opinion between the Japanese government and its two field armies, the Shanghai Expeditionary Army and the 10^th Army, which by November were both nominally under the control of the Central China Area Army commanded by Matsui. Matsui had made it clear to his superiors even before he left for Shanghai that he wished to march on Nanking as he was convinced that the conquest of Nanking, the Chinese capital, would trigger the fall of China’s nationalist government and thus give Japan a rapid and complete victory in its war with China. Like Matsui, Yanagawa was eager to take Nanking, and both generals chafed under the operation restriction line that had been imposed on them by the army general staff.

On 19 November Yanagawa ordered his 10^th Army to pursue the retreating Chinese forces across the operation restriction line to Nanking, a flagrant act of insubordination. When he discovered this on the following day, Tada ordered Yanagawa to come to an immediate halt, but this instruction was ignored. Matsui made some effort to restrain Yanagawa, but also told him that he could send some advance units beyond the line. In fact, Matsui was highly sympathetic with Yanagawa’s actions and, a few days later on 12 November, sent an urgent telegram to the army general staff insisting that in order to 'resolve this crisis in a prompt manner we need to take advantage of the enemy’s present declining fortunes and conquer Nanking…By staying behind the operation restriction line at this point we are not only letting our chance to advance slip by, but it is also having the effect of encouraging the enemy to replenish their fighting strength and recover their fighting spirit and there is a risk that it will become harder to completely break their will to make war.'

Meanwhile, as increasing numbers of Japanese formations and units continued to slip past the operation restriction line, Tada was also coming under pressure from within the army general staff. Many of Tada’s colleagues and subordinates, including Major General Sadamu Shimomura, the powerful chief of the general staff’s operations division, had come round to Matsui’s viewpoint and wanted Tada to approve an attack on Nanking. On 24 November Tada finally relented and removed the operation restriction line 'owing to circumstances beyond our control', and then several days later reluctantly approved the operation to seize Nanking. Tada flew to Shanghai on 1 December to deliver the order in person, though by then his own armies in the field were already well on their way to Nanking.

On 15 November, near the end of the 'Battle of Shanghai', Chiang convened a meeting of the Military Affairs Commission’s Supreme National Defence Council for a strategic planning effort, including a decision on what to do in the event of a Japanese attack on Nanking, for which Chiang insisted strongly that there be a sustained defence. Chiang argued, just as he had during the 'Battle of Shanghai', that China would be more likely to receive aid from the great powers, possibly at the ongoing Nine-Power Treaty Conference, if it could prove on the battlefield its will and capacity to resist the Japanese. Chiang also noted that holding Nanking would strengthen China’s hand in peace talks which he wanted the German ambassador, Oskar Trautmann, to mediate.

Chiang ran into stiff opposition from his officers, including General 1^st Rank He Yingqin, the powerful chief-of-staff of the Military Affairs Commission, General 2^nd Rank Bai Chongxi, the deputy chief-of-staff, Major General Li Zongren, commander of the 5^th War Zone, and his German adviser, the retired Generalleutnant Alexander von Falkenhausen.These men argued that the Chinese army needed more time to recover from its losses at Shanghai, and pointed out that in topographical terms Nanking was essentially indefensible. As far as this last was concerned, the mostly gently sloping terrain in front of Nanking would make it easy for the Japanese to advance on the city, while the Yangtze river behind Nanking cut the defenders' line of retreat.

Chiang, however, had become increasingly agitated during the 'Battle of Shanghai', even angrily declaring that he would stay behind in Nanking alone and command its defence personally. But just when Chiang believed himself completely isolated, Tang, an ambitious senior member of the Military Affairs Commission, spoke in support of Chiang’s position, although accounts vary on whether Tang spoke with enthusiasm or reluctance. Seizing this opportunity, Chiang responded by organising the Nanking Garrison Force on 20 November and appointing Tang as its commander on 25 November. The orders Tang received from Chiang five days later were to 'defend the established defence lines at any cost and destroy the enemy’s besieging force'.

Though both men publicly declared that they would defend Nanking 'to the last man', they were fully aware of the situation’s highly precarious nature. On the same day that the Nanking Garrison Force was established Chiang officially moved the capital of China from Nanking to Chungking deeper in China’s interior. Furthermore, both Chiang and Tang would at times give contradictory orders on whether their mission was to defend Nanking to the death or merely delay the Japanese advance.

Following the Manchurian Incident of 1931 (a false flag event staged by Japanese military personnel as a pretext for the Japanese invasion of Manchuria), the Chinese government had embarked on a high-priority national defence programme with massive construction of primary and auxiliary air force bases, including that at Jurong, around Nanking to facilitate air defence as well as launching counter-offensives against any hostile incursions. On 15 August 1937 the Imperial Japanese Navy launched the first of many heavy fast bomber raids against Jurong air base using the advanced Mitsubishi G3M 'Nell' twin-engined bomber operating conceptually on the concepts of the Italian air power theorist Giulio Douhet: these constituted an attempt to neutralise the Chinese air force fighter strength defending the capital city, but were severely repulsed by the unexpected heavy resistance and performance of the fighters based at Jurong, and suffering a loss rate of almost 50%.

On 20 November, Chinese army troops and teams of conscripted labourers began the hurried strengthening of Nanking’s defences both inside and outside the city. Nanking itself was surrounded by formidable stone walls with a circumference of almost 30 miles (48 km). Constructed hundreds of years earlier, the walls rose to a height of 65 ft (20 m), were 30 ft (9.1 m) thick, and in more recent times had been studded with machine gun emplacements. By 6 December, all the gates into the city had been closed and barricaded with an additional layer of sandbags and concrete some 20 ft (6.1 m) thick. Outside the walls a series of semi-circular defence lines were built in the path of the Japanese advance, most notably an outer line about 10 miles (16 km) from the city and an inner line, known as the Fukuo Line, directly outside the city. The Fukuo Line was a sprawling network of trenches, moats, barbed wire entanglements, minefields, gun emplacements and pillboxes, and was seen as the city’s final outer defence. There were also two key high points on the Fukuo Line, namely the peaks of Zijinshan to the north-east and the plateau of Yuhuatai to the south, where the fortification was especially thick. In order to deny the Japanese shelter or local supplies, Tang adopted a scorched-earth strategy on 7 December, ordering the incineration of all buildings in the path of the Japanese within 0.6 and 1.2 miles (1 and 2 km) of the city, as well as the destruction of all homes and structures near roads within 10 miles (16 km_ of the city.

The Nanking Garrison Force was, at least on paper, a formidable army of 13 divisions, including three elite German-trained formations and the super-elite Training Brigade, but in reality most of these had trickled back to Nanking after being mauled severely in the 'Battle of Shanghai'. By the time they reached Nanking, the formations were physically exhausted, short of equipment and severely under-strength in numerical terms. To rebuild some of these formations and units, 16,000 young men and teenagers from Nanking and the rural areas surrounding it were conscripted as new recruits, and an additional 14,000 soldiers were transferred from Hankou to refill the 2^nd Army’s ranks. As a result of unexpected speed of the Japanese advance, however, most of the conscripts received only rudimentary weapons training on their way to or upon their arrival at the front lines. No definitive statistics exist on how many soldiers the Nanking Garrison Force had managed to group together by the time of the battle, but estimates place the number at anything between 73,790 to 150,000.

During this period, the Imperial Japanese Navy’s air force undertook frequent raids on the city, eventually totalling 50 according to the navy’s own records. The Imperial Japanese Navy air force had struck Nanking for the first time on 15 August with G3M 'Nell' twin-engined medium bombers, which were deemed heavy bombers by the Japanese, but suffered heavy losses to the defence put up by the Chinese air force’s Boeing P-26 (Model 281) 'Peashooter' monoplane and Curtiss Hawk II and Hawk III biplane fighters, each powered by a single engine, operating primarily from Jurong air base. It was not until after the introduction of what was at the time the advanced Mitsubishi A5M 'Claude' single-engined fighter did the Japanese begin to turn the tide in air-to-air combat, and proceed with bombing both military and civilian targets day and night with increasing impunity as the Chinese aerial losses mounted through continuous attrition. The Chinese did not have either the aircraft industry or the comprehensive training regimen to replace men and machines with which to tackle the ever-growing and ever-improving Japanese war machine. Experienced veteran Chinese fighter pilots still proved a most dangerous adversary against Japanese air power: 'aces' such as Colonel Gao Zhihang, Major John Wong Pan-yang and Captain Liu Cuigang, flying fighters which were outnumbered by the superior A5M machines entering Nanking on 12 October, on that day shot down four A5M fighters, including a double kill by Gao. Both Gao and Liu had been lost in non-combat incidents by the following month as they were preparing to receive an improved fighter in the form of the Polikarpov I-16.

In the face of Japanese terror bombing and the continuing Japanese land advance, the large majority of Nanking’s civilians fled the city: by a time early in December, Nanking’s population had dropped from its former total of more than one million to less than 500,000, a figure which included Chinese refugees from rural villages burned down by their own government’s scorched-earth policies. Most civilians still in the city were very poor and had nowhere else to go. The city’s foreign residents were also requested on several occasions to depart the city, which was becoming more and more chaotic under the strain of bombings, fires, looting by criminals, and electrical outages, but those few foreigners brave enough to stay behind attempted to find a way to help the Chinese civilians who had been unable to leave. Late in November, a group of them led by John Rabe, a German businessman, created the Nanking Safety Zone in the city centre: this was a self-proclaimed demilitarised zone in which, it was hoped, civilians could congregate to escape the fighting. The safety zone was recognised by the Chinese government, and on 8 December Tang ordered all remaining civilians to move into the zone.

Among the Chinese who did manage to escape Nanking were Chiang and his wife Soong Mei-ling, who had flown out of Nanking on a private aeroplane just before dawn on 7 December. The mayor of Nanking and most of the municipal government left on the same day, entrusting management of the city to the Nanking Garrison Force.

By the start of December, the Central China Area Army had reached a strength of more than 160,000 men, although only about 50,000 of these eventually became involved in the fighting for Nanking. The Japanese planned to tackle Nanking in a pincer movement which the Japanese called an 'encirclement and annihilation'. The two arms of the Central China Area Army's pincer were the Shanghai Expeditionary Army advancing on Nanking from its eastern side and the 10^th Army advancing from its southern side. To the north and west of Nanking lies the Yangtze river, which the Japanese saw as a possible Chinese escape route and therefore schemed to plug by the despatch of a squadron of ships up the river and by deploying two special detachments to circle around behind the city. Of the latter, ther 'Kunisaki' Detachment was to cross the Yangtze river in the south with the ultimate aim of occupying Pukou on the river bank to the west of Nanking, and the 'Yamada' Detachment was to be sent on the far northern route with the ultimate aim of taking Mufushan just to the north of Nanking.

Together with the army general staff, Matsui envisaged a slow and steady march on Nanking, but his subordinates refused to comply and instead raced eagerly with each other to be the first to get to the city. Soon all the Japanese formations and units were advancing at the breakneck pace of as many as 25 miles (40 km) per day: the 10^th Army, for instance, captured the key town of Guangde on 30 November, three days before it was even supposed to start its advance, and the 'Shanghai Expeditionary Army took Danyang on 2 December, more than five days ahead of schedule. In order to achieve such speeds, the Japanese troops carried little more than their personal weapons and ammunition. As they were marching well ahead of most of their supply lines they had to purchase or loot their food from Chinese civilians along the way.

During their advance, the Japanese overcame initially light resistance from the already battered Chinese forces being pursued from Shanghai by the Japanese in what was described as a 'running battle'. Here the Japanese were aided by their complete air supremacy, their abundance of tanks, the improvised and hastily constructed nature of the Chinese defences, and the Chinese strategy of concentrating their defending forces on small patches of relatively high ground, which rendered them easy to outflank and surround.

On 5 December, Chiang visited a defensive encampment near Jurong to boost the morale of his men, but was forced to retreat when the Japanese began their attack. On that day the Shanghai Expeditionary Army's rapidly advancing elements occupied Jurong and then reached Chunhuazhen, a key point of Nanking’s outer defence line, and this put Japanese artillery within range of the city. Here the 51^st Division flung its main force into the fighting and repeatedly repulsed Japanese attacks before cracking on 8 December, when the main force of the Shanghai Expeditionary Army arrived, taking the fortress at Zhenjiang and the spa town of Tangshuizhen on that same day. Meanwhile, on the southern side of the same defence line, armoured vehicles of the 10^th Army charged the Chinese position at Jiangjunshan and Niushoushan defended by the 58^th Division. Chinese soldiers equipped with hammers jumped onto the Japanese vehicles and banged repeatedly on their roofs, but after the fall of night the 58^th Division was finally overwhelmed on 9 December after suffering, according to its own records, 800 casualties.

By 9 December, the Japanese advance had reached Nanking’s innermost defence line, the daunting Fukuo Line. At this point Matsui had a summons to surrender drawn up, and this implored the Chinese to send military envoys to Nanking’s Zhongshan gate to discuss terms for the peaceful occupation of the city, and he then had a Mitsubishi Ki-21 'Sally' twin-engined medium bomber scatter thousands of copies of the message over the city. On 10 December, a group of Matsui’s senior staff officers waited to see if the gate would be opened, but Tang had no intention of responding. Later in the same day, Tang proclaimed to his men that 'Our army has entered into the final battle to defend Nanking on the Fukuo Line. Each unit shall firmly defend its post with the resolve to either live or die with it. You are not permitted to retreat on your own, causing the defence to collapse.'

At 13.00 on 10 December, Matsui ordered all his formations and units to launch a full-scale attack on Nanking. That day the Shanghai Expeditionary Army fell on the super-elite Training Brigade on the peaks of Zijinshan, which dominate Nanking’s north-eastern aspect. Clambering up the ridges of the mountain, the men of the Shanghai Expeditionary Army faced the painstakingly difficult task of wresting control of a succession of Chinese positions in bloody infantry charges. Advancing along the southern side of Zijinshan was no easier as Matsui had forbidden his men from using artillery in that location as he was deeply committed to inflicting no damage on its two famous historical sites, the mausoleums of Sun Yat-sen and Ming Xiaoling.

Also on Nanking’s eastern side but farther to the south, other units of the Shanghai Expeditionary Army faced the difficulties of fording the large moat between them and Nanking’s Zhongshan, Guanghua and Tongji gates, though the speed of their earlier advance aided the Japanese as key Chinese units earmarked for deployment in this sector were were not yet in position. That evening, Japanese engineers and artillerymen closing in on the Guanghua gate blew a hole in the wall, and a Japanese battalion launched a daring attack through the gap and planted a Japanese flag on a portion of the gate before being pinned by a series of determined Chinese counterattacks. The Chinese brought up reinforcements, including tanks, and deluged the Japanese battalion with grenades and flaming petrol-soaked lumbers. The Japanese battalion was saved from destruction only by timely bursts of concentrated artillery fire from the rest of its division. The battalion managed to hold its position for the rest of the battle despite losing 80 of its 88 men.

At the same time, the 10^th Army was storming Yuhuatai, a rugged plateau directly in front of the Zhonghua gate on Nanking’s southern side. The 10^th Army's progress was slow and casualties were heavy as Yuhuatai was built like a fortress of interlocking pillboxes and trenches manned by three Chinese divisions, including the German-trained 88^th Division, though the Chinese were also apt to counterattack and some Japanese units were forced to spend more time defending than attacking. Almost every man that the 88^th Division had deployed on Yuhuatai was killed in action, including three of its four regimental commanders and both of its brigade commanders, but in the process the Japanese were made to suffer 2,240 casualties, including 566 dead. Yuhuatai was finally overrun at 12.00 on 12 December.

Behind Yuhuatai, the 88^th Division had stationed its barely trained new recruits above Nanking’s Zhonghua gate. During the previous night the Japanese had attempted to infiltrate a 'suicide squad' carrying explosive charges up to this gate in an attempt to blow a hole in it, but the squad became lost in the morning fog and failed to reach the wall. At 12.00 on 17 December a group of six Japanese soldiers managed to cross the moat in a small boat, scale the wall at Zhonghua gate on a shaky bamboo ladder and raise the Japanese flag: five of the men were killed, but the last seized a Chinese machine gun and held the position on his own. Soon after this, another Japanese team ignited a fire in front of the gate to create a smokescreen. By 17.00 increasing numbers of Japanese troops were crossing the moat and overrunning the Zhonghua gate position by the use of makeshift bridges that their engineers had to hold them up with their own bodies, and with the help of some well-directed Japanese artillery fire from the top of Yuhuatai parts of the wall finally crumbled. Meanwhile, just to the west of Zhonghua gate, other soldiers of the 10^th Army had driven a hole through the Chinese lines in the wet ground to the south of Shuixi gate and were launching a drive on that gate with the support of a tank force.

At the height of the battle, Tang complained to Chiang that 'Our casualties are naturally heavy and we are fighting against metal with merely flesh and blood', but what the Chinese lacked in equipment they compensated in the sheer ferocity with which they fought. Over the course of the battle, about 1,000 Chinese soldiers were shot by other members of their own army for attempting to retreat, and on Yuhuatai Japanese soldiers noticed that many Chinese pillboxes were chained from the outside to prevent their occupants from fleeing.

The Japanese were gaining the upper hand over the hard-pressed and isolated Chinese defenders. On 12 December the Shanghai Expeditionary Army captured Peak No. 2 of Zijinshan, and from this vantage point unleashed a torrent of artillery fire at Zhongshan gate, causing a large portion of the wall suddenly to collapse. After the fall of night, the fires that blazed out of control on Zijinshan were visible even from Zhonghua gate in the south, which was completely occupied by the 10^th Army on the night of 12/13 December.

Unknown by the Japanese, however, was the fact that Chiang had already ordered Tang to abandon the defence: despite his earlier talk about holding Nanking to the bitter end, Chiang telegraphed an order to Tang on 11 December to abandon Nanking. Tang prepared to do so on the following day, but startled by Japan’s intensified onslaught he made a frantic last-minute bid to negotiate a temporary ceasefire with the Japanese through two German civilians, John Rabe and Eduard Sperling. Only when it became clear that the negotiations would be unsuccessful did Tang finally finish drawing up a plan calling for all his units to launch a co-ordinated break-out from the Japanese encirclement under cover of darkness at 23.00 on that night and then muster in Anhui. Just after 17.00 on 12 December, Tang arranged for the plan to be transmitted to all units, and then crossed the Yangtze river, escaping through the city of Pukou on the opposite bank of the river less than 24 hours before it was occupied by the 'Kunisaki' Detachment.

By the time Tang slipped out of the city, however, the entire Nanking Garrison Force was rapidly disintegrating, and some units were in open flight. Furthermore, contact had already been lost with many units which therefore did not received Tang’s message and continued to hold their positions as ordered. Even those units which did receive the order enjoyed little success in slipping through the Japanese lines.The Chinese LXVI Corps and LXXXIII Corps made a bid to evade the Japanese through a gap to the east, but immediately entered their own minefield. After this they were attacked, even as they fled, by Japanese units and lost two divisional chiefs-of-staff in combat. Although the two corps had started the battle with at least 11,000 men, only 600 escaped Nanking. Near dawn on 13 December, a portion of the Chinese LXXIV Corps was also annihilated in a bid to break through the Japanese lines along the Yangtze river to the south of Nanking.

One of the few units which did succeeded in escaping from Nanking was General 2^nd Rank Xu Yuanquan’s Chinese 2^nd Army, which was situated just to the north of Nanking. Though he had not received Tang’s order to abandon the defence, on the night of 12 December Xu had heard that Nanking had been captured and decided to withdraw. During the night he managed to evacuate most of his formation across the Yangtze river just before a Japanese naval blockade was instituted.

During the same night, a huge mass of many thousands of Chinese soldiers and civilians from the southern side of Nanking in an effort to escape the 10^th Army's advance was prevented from reaching the harbour at Xiaguan by Chinese security troops, who fired on the crowd for retreating without permission and managed to hold it back. At 21.00, a fleeing Chinese tank unit, which had also not received Tang’s parting message, charged the security troops and burst through their block, only for the crowd then to discover that there were hardly any boats in the harbor. The crowd fought to clamber aboard what few craft were available, but these soon became so overloaded that they sank. Most of the surviving Chinese soldiers took to the Yangtze river’s rough and frigid waters clinging to logs and pieces of timber, and most were quickly swallowed by the river. Moreover, by this time the Japanese encirclement of Nanking was virtually complete and many of those attempting to brave the Yangtze river soon found themselves under fire from both sides of the river. Seeing this, others turned back to the city in despair.

Many tens of thousands of Chinese soldiers unable to escape the city threw off their uniforms and abandoned their weapons, switching to clothes often stolen from passing civilians, and mingled with civilians to seek sanctuary in the Nanking Safety Zone.

The fighting in Nanking did not end entirely on the night of 12/13 December, when the Japanese took the remaining gates and entered the city. During their mopping-up operations in the city the Japanese continued for several more days to beat back sporadic resistance from Chinese stragglers. Although Mufushan, just to the north of Nanking, was taken by the 'Yamada' Detachment without much bloodshed on the morning of 14 December, pockets of resistance outside Nanking persisted for several more days.

Meanwhile, the Japanese units mopping up in Nanking had decided that the former Chinese soldiers hiding in the city were a security risk and therefore carried out a thorough search of every building in Nanking and made frequent incursions into the Nanking Safety Zone. Japanese units attempted to distinguish former soldiers from civilians by checking if they had marks on their shoulders from wearing a backpack or carrying a rifle. The criteria employed were often arbitrary, however, as was the case with one Japanese company which apprehended all men with 'shoe sores, calluses on the face, extremely good posture, and/or sharp-looking eyes' and for this reason many civilians were also taken at the same time. What happened to the Chinese soldiers and civilians who were captured varied greatly from unit to unit, though many were summarily executed in an event that came to be known as the Nanking Massacre, an event which the foreign residents and journalists in Nanking made known internationally within days of the city’s fall. The Japanese also committed random acts of murder, rape, looting and arson during their occupation of Nanking. The post-war International Military Tribunal for the Far East came to the conclusion that the total number of civilians and prisoners of war murdered in Nanking and its region during the first six weeks of the Japanese occupation was more than 200,000. and that 20,000 women were raped, including infants and the elderly. Estimates for the total death toll of the Nanking Massacre vary widely.

The Japanese mopping-up operations and the large-scale massacres that accompanied them were over by the afternoon of 17 December, when Matsui entered Nanking for a victory parade. By the end of December most Japanese soldiers had left Nanking, although some units of the Shanghai Expeditionary Army remained to occupy the city. The Nanking Self-Government Committee, a new municipal authority formed from local Chinese citizens, was inaugurated on 1 January 1938, but it was not until 25 February that all restrictions on the free movement of civilians into and out of the city were lifted.

News of the massacre was tightly censored in Japan, in which the capture of Nanking triggered a frenzy of excitement among the citizenry. Mass celebrations of every sort, either spontaneous or sponsored by the government, took place throughout the country.

Their seizure of Nanking had been accomplished more speedily and more easily than the Japanese had foreseen, and the Japanese lost only 1,953 men killed and 4,994 men wounded. Japan’s casualties were undoubtedly dwarfed by those of China, though no precise figures exist on how many Chinese were killed in action. The Japanese claimed to have killed as many as 84,000 men during the Nanking campaign, whereas a contemporary Chinese source claimed that the army suffered 20,000 casualties. What is clear, however, is that the Japanese inflated their opponent’s losses while the Chinese had reason to downplay the scale of their losses.

An official report of the Chinese government soon argued that an excess of untrained and inexperienced troops was a major cause of the defeat, but at the time Tang was made to bear much of the blame, and later historians have also criticised him. Some Japanese histories have characterised Tang’s battlefield leadership as incompetent, arguing that an orderly withdrawal from Nanking may have been possible if Tang had carried it out on 11 December or if he had not himself fled his post well in advance of most of his beleaguered units. However, Chiang’s very decision to defend Nanking is also controversial: one Japanese historian argued that Chiang chose 'almost entirely out of emotion' to fight a battle he knew he could only lose, and a Chinese historian argued that the decision is often regarded as one of 'the greatest strategical mistakes of the Sino-Japanese war'.

Despite its military accomplishment in taking Nanking, Japan’s international reputation was blackened by the Nanking Massacre and by a series of international incidents that occurred during and after the battle. Most notable of these were the shelling by Japanese artillery of the British steamship Ladybird on the Yangtze river on 12 December, and the sinking by Japanese aircraft of the US gunboat Panay not far downstream on the same day. The so-called 'Allison incident' when a Japanese soldier slapped a US consul, further exacerbated tensions between Japan and the USA.

The loss of Nanking did not force China to capitulate as Japan’s leaders had predicted. Even so, buoyed by their victory, the Japanese government replaced the lenient terms for peace which they had relayed to the mediator, Oskar Trautmann, the German ambassador to China, before the battle with an extremely harsh set of demands that were ultimately rejected by China. On 27 December, Chiang delivered a passionate speech defiantly declaring that 'The outcome of this war will not be decided at Nanking or in any other big city; it will be decided in the countryside of our vast country and by the inflexible will of our people…In the end we will wear the enemy down. In time the enemy’s military might will count for nothing. I can assure you that the final victory will be ours.'