The Japanese began a very aggressive course of action with a contrived clash with China as far back as September 1931 which resulted in the occupation of Manchuria.
In February 1933 after being severely censured regarding the aggressive action with China, Japan withdrew from The League of Nations.
Further Japanese instigated contrived clashes with China precipitated war between the two countries,
The First Sino - Japanese War was a major conflict between the Japanese and China {The Qing Dynasty} over the control of Korea. The War was fought between 1st August 1894 and April 17th 1895
The war actually exposed the feebleness of China under the Qing Dynasty and demonstrated the success of modernisation in Japan since the Meiji Restoration.
The war resulted in a shift of regional dominance in Asia from China to Japan. Historians hesitate not in stating that this First Sino-Japanese War lead to the Revolution in 1911.
Japan and China fought intermittently from 1931 full scale war between the two countries started in 1937
1939 was certainly the ?'Year' which saw the real commencement of World War 11.
1939;- Japan Invaded Hainan Island.
Germany invaded Poland
Britain and France declared War on Germany.
1940 Germany Invaded Denmark and Norway, The Netherlands, Belgium and France.
1941 Germany Invaded Russia
Japan Invaded Hong Kong, Malaya and Thailand.
Japan bombed Pearl Harbour, Guam and the Philippines
Japan Sank HMS Prince of Wales and HMS Repulse, giving Japan total control of the Pacific..
Japan Invaded Burma via Thailand.
1942 Japan and Thailand sign a treaty of co-operation.
Thailand declares War on The United States of America and Great Britain
In excess of five thousand civilians died in the first two days of air raids on China in 1939.
Historian consider that in excess of 300,000 people perished in the Nanking Massacre , some Japanese Historians deny such a massacre happened at all.
By 1940 China's air force was virtually wiped out, the country did not have the means to replace air-craft lost in combat.
During the next few years Japan mercilessly bombed civilian targets on almost every major city in China leaving untold millions dead, injured and homeless.
Japanese marines at Guangdong in the Battle of Wuhan .
{The above photograph was taken from the internet}
The Japanese used a strategy of creating friendly puppet governments in the occupied territories of China.
They succeeded in recruiting and training a Collaborationist Chinese Army to maintain control of the public and ensure security in occupied areas.
The fighting reached a stalemate situation by 1940 in china, Japan held almost all of the eastern coast of China and Vietnam, however guerrilla fighting was rampaging through the occupied areas but China did not have the technology, infrastructure or industrial capacity to launch a modern warfare counter attack against Japan.
General Chiang Kai-Shek had lost the best part of his army defending Shanghai, he was really at the mercy of his Generals who maintained a high degree of independence from the central KMT {Kuomintang or Chinese Nationalist Party} government.
Japan had suffered heavy losses from the unexpected and very effective stubborn resistance in China and was experiencing great difficulties in managing the conquered and seized territories.
We certainly were not seeing the type of progress in China which Germany was getting in Europe, that's for sure.
You can of course Google The Nanking Massacre for yourself, there are some outstanding accounts.
OK I got carried away again, but the introduction is quite important I think.
The British had considered building a railroad linking Thailand with Burma many years before the War but had shelved the idea due to the numerous difficulties envisaged and predicted.
Plus they did not have ?'unlimited slaves' to do the donkey-work.
The Japanese did however use the same route which the British had considered using.
The Japanese had made use of railways as part of their mode of operation throughout Asia and soon after Japan and Thailand signed their agreement of co-operation the Commanding Officer of Southern Region Army's 2 Railway Control in Thailand, Major General Hattori ordered that construction of a railroad begin linking Nong Pladuk in Thailand to Thanbyuzayat in Burma.
Due to the inhospitable and difficult terrain, there was no chance of using heavy construction machinery, they assessed that a workforce of some 60,000 inclusive of 10,000 prisoners of war would be required to build the same.
After losing the battle of Midway and the heavy losses incurred by the Japanese Navy the long sea voyage around the Malay Peninsula to Rangoon became a more perilous undertaking for the Japanese and the railroad became a project of vital importance to the Japanese war Machine.