Known as the Chinese People's Anti-Japanese War of Resistance ( 中国人民抗日战争 ) , or Eight Years' War of Resistance ( 八年抗战 ) , the Second Sino-Japanese War is a major invasion of eastern China by Japan preceding and during World War II. The conflict lasted for 97 months and 3 days (measured from 1937 to 1945).

This cruel War began with Battle of Lugou Bridge ( 卢沟桥事变 ) on July 7, 1937. Following this event, the Japanese occupied Shanghai, Nanjing and Southern Shanxi as part of campaigns involving approximately 200,000 Japanese soldiers, and considerably more Chinese soldiers. It is estimated that as many as 300,000 people were perished in the Nanjing Massacre ( 南京大屠杀 ) , after the fall of Nanjing. By then the Chinese Nationalist army had fled the city and the Japanese entered a virtually resistance-free city. The time period of the Massacre is not clearly defined, though the period of unruly carnage lasted well into 6 weeks after, until early February 1938.

War crimes committed during this episode include looting, rape, arson and the killing of civilians and prisoners of war. It is not known how many Nationalist soldiers were trapped within the walled city and disguised themselves as civilians, but a large number of deaths also occurred to women and children.

The Lugou Bridge Incident not only marked the beginning of an open, undeclared, war between China and Japan, but also hastened the formation of the second Kuomintang ( 国民党 ) －Communist Party of China ( 中国共产党CCP ) United Front. The distrust between the two antagonists was scarcely veiled. Their alliance was forged literally at gun point when Chiang Kai-shek ( 蒋介石 ) was held in the Xian incident ( 西安事变 ) and forced to ally with the CCP. The uneasy alliance began breaking down by late 1938, despite Japan's steady territorial gains in northern China, the coastal regions, and the rich Yangtze RiverValley in central China. After 1940, conflict between the Nationalists and Communists became more frequent in the areas outside Japanese control. The Communists expanded their influence, through mass organizations, administrative reforms, land and tax reform measures favoring peasants -- and the Nationalists attempted to restrict the spread of Communist influence.

The Japanese had no capability of directly administering China. Their goal was to set up friendly puppet governments favorable to Japanese interests. However, the atrocities of the Japanese army made the governments that were set up very unpopular.

Compared to Japan, China was unprepared for war and had little military industrial strength, few mechanized divisions, and virtually no armor support. Up until the mid 1930s China had hoped that the League of Nations would provide countermeasures to Japan's aggression. In addition, the Kuomintang government was mired in an internal war against the Communists. Chiang famouslyquoted "the Japanese are a disease of skin, the Communists are a disease of the heart". Though the communists formed the New Fourth Army ( 新四军 ) and the 8th Route Army ( 八路军 ) which were under the command of the National Revolutionary Army, the Unified Front was never truly unified. All these disadvantages forced China to adopt a strategy whose first goal was to preserve its army strength, whereas a full frontal assault on the enemy would often prove to be suicidal. Also, pockets of resistance were to be continued in occupied areas to pester the enemy and make their administration over the vast lands of China difficult. As a result the Japanese really only controlled the cities and railroads.

However, Chiang realized that in order to win the support from the United States or other foreign nations, China must prove that it was indeed capable of fighting. A fast retreat would discourage foreign aid so Chiang decided to make the Battle of Shanghai ( 淞沪会战 ) his grand stage. Chiang sent his elite German trained army to defend China largest and most commercialized city from the Japanese. The battle saw heavy casualties on both sides and ended with a Chinese retreat. While the battle was a military defeat for the Chinese, it proved that China was not willing to be defeated and showcased the Chinese determination to the world. The battle lasted over three months and proved to be an enormous morale booster.

While this direct army to army fighting lasted during the early phases of the war, large numbers of Chinese defeats compared to few victories eventually led to the strategy of stalling the war. Large areas of China were conquered during the early stages of the war but the Japanese advancements began to stall. The Chinese strategy at this point was to prolong the war until it had sufficient foreign aid to defeat the Japanese. Kuomintang engaged in a practice of scorched earth ( 焦土政策 ) in an attempt to slow down the Japanese. Dams and levees were sabotaged which led to the 1938 Huang He flood. By 1940, the war had reached a stalemate with both sides making minimal gains. The Chinese had successfully defended their land from oncoming Japanese on several occasions while strong resistance in areas occupied by the Japanese made a victory seem impossible to the Japanese. This frustrated the Japanese and led them to employ a policy of "burn all, kill all, destroy all" ( 三光政策 ) . It was during this time period that a bulk of Japanese atrocities were committed.

In 1941, the Japanese attacked Pearl Harbor which brought the United States into the war. China officially declared war on Japan on 8 December. It refused to declare war earlier because receiving military aid while officially at war would break the neutrality of the donor nation. At this point, the strategy changed from survival to minimizing warfare. Chiang realized that the Americans would do a bulk of the fighting and were better equipped to fight the Japanese so he decided to curtail the activities of his army and focus on the potential civil war after the war..

The basis of Chinese strategy during the war, which can be divided into three periods:

First Period: 7 July 1937 (Battle of LugouBridge) - 25 October 1938 (Fall of Hankou). In this period, one key concept is the trading of "space for time" ( 以空间换取时间 ) . The Chinese army would put up token fights to delay Japanese advance to northeastern cities, to allow the home front, along with its professionals and key industries, to retreat further west into Chongqing to build up military strength.

Second Period: 25 October 1938 (Fall of Hankou) - July, 1944. During the second period, the Chinese army adopted the concept of "magnetic warfare" to attract advancing Japanese troops to definite points where they were subjected to ambush, flanking attacks, and encirclements in major engagements. The most prominent example of this tactic is the successful defense of Changsha (长沙) numerous times.

Third Period: July 1944 - 15 August 1945. This period employs general full frontal counter-offensive. As of mid 1945, all sides expected the war to continue for at least another year. However it was suddenly ended by the dropping of the two atomic bombs on Hiroshima and Nagasaki. Japan capitulated to the allies on August 14, 1945. The Japanese troops in China formally surrendered on September 9, 1945 and by the provisions of the Cairo Conference of 1943 the lands of Manchuria, Taiwan and the PescadoresIslands reverted to China.

In 1945 China emerged from the war nominally a great military power but actually a nation economically prostrate and on the verge of all-out civil war. The economy deteriorated, sapped by the military demands of foreign war and internal strife, by spiraling inflation, and by Nationalist profiteering, speculation, and hoarding. Starvation came in the wake of the war, and millions were rendered homeless by floods and the unsettled conditions in many parts of the country. The situation was further complicated by an Allied agreement at the Yalta Conference in February 1945 that brought Soviet troops into Manchuria to hasten the termination of war against Japan. Although the Chinese had not been present at Yalta, they had been consulted; they had agreed to have the Soviets enter the war in the belief that the Soviet Union would deal only with the Nationalist government. After the war, the Soviet Union, as part of the Yalta agreement's allowing a Soviet sphere of influence in Manchuria, dismantled and removed more than half the industrial equipment left there by the Japanese. The Soviet presence in northeast China enabled the Communists to move in long enough to arm themselves with the equipment surrendered by the withdrawing Japanese army. The problems of rehabilitating the formerly Japanese-occupied areas and of reconstructing the nation from the ravages of a protracted war were staggering, to say the least.

The war left the Nationalists severely weakened and their policies left them unpopular. Meanwhile the war strengthened the Communists, both in popularity and as a viable fighting force. At Yan'an and elsewhere in the "liberated areas," Mao was able to adapt Marxism-Leninism to Chinese conditions. He taught party cadres to lead the masses by living and working with them, eating their food, and thinking their thoughts. When this failed, however, more repressive forms of coercion, indoctrination and ostracization were also employed. The Red Army ( 红军 ) fostered an image of conducting guerrilla warfare in defense of the people. In addition, the CCP was effectively split into "Red" (cadres working in the "liberated" areas) and "White" (cadres working underground in enemy-occupied territory) spheres, a split that would later sow future factionalism within the CCP. Communist troops adapted to changing wartime conditions and became a seasoned fighting force. Mao also began preparing for the establishment of a new China, well away from the front at his base in Yan'an. In 1940 he outlined the program of the Chinese Communists for an eventual seizure of power and began his final push for consolidation of CCP power under his authority. His teachings became the central tenets of the CCP doctrine that came to be formalized as Mao Zedong Thought. With skillful organizational and propaganda work, the Communists increased party membership from 100,000 in 1937 to 1.2 million by 1945. Soon, all out war broke out between the KMT and CPC, a war that would leave the Nationalists banished to Taiwan and the Communists victorious on the mainland.

To this day the war is a major point of contention between China and Japan.

A small but vocal group of Japanese nationalists and/or right-wingers deny a variety of crimes attributed to Japan. The Japanese invasion of its neighbours is often glorified or whitewashed, and wartime atrocities, most notably the Nanjing Massacre ( 南京大屠杀 ) , comfort women ( 慰安妇 ) , and Unit 731 ( 731部队 ) , are frequently denied by such individuals. The Japanese government has also been accused of historical revisionism by allowing the approval of school textbooks omitting or glossing over Japan's militant past.

In the PRC, citizens are frequently reminded of the exploits of the heroes of the Anti-Japanese War of Resistance. In its response to global criticism of Japanese textbook revisionism, the PRC government has been accused of using this incident to stir up already growing anti-Japanese feelings to whip up nationalistic sentiments and divert its citizens' minds from internal matters.

But political issue or not, the war remains a major roadblock for Sino-Japanese relations today, and many people, particularly in China, harbour grudges over the war and related issues.