The Japanese campaign in the Shan States was a shrewd tactical maneuver in the battle for Burma. It hastened the fall of Burma by weeks, if not months, and increased greatly the amount of materiel captured by the invaders or which had to be destroyed by the British and Chinese. The righting began in that area in mid-March with patrol action on the Thailand border of Karenni, a small British protectorate adjoining the Shan States on the south; but it was not until April, following the fall of Toungoo, Burma, that serious fighting occurred. Previously the only approach the Japanese had to this mountainous district was by boat up the swift, treacherous Salween river, or over jungle trails from Thailand. But with the capture of Toungoo at the end of March, they had a road from Burma to Karenni and on to the Shan States.

The origin of Japan's interests in Manchuria may be regarded as the base-point from which during the past half century a variety of economic, political and territorial ambitions has radiated, enveloping today virtually all of Eastern Asia and leading directly to war with the United States and Great Britain. In the historical development of this vast program of overseas expansion, paramount attention is usually centered on the vigorous activity which characterized Japanese relations with the ancient kingdom of Korea during the second half of the nineteenth century. This movement played a vital part in shaping Japanese imperialism, but it is significant to recall that Japan's first bid for an actual territorial position on the continent was not concerned with Korea. The fiction of Korean independence was supported by Japanese statesmen until 1910, when Korea was finally annexed to Japan. On the other hand, Japanese territorial ambitions on the mainland were positively revealed fifteen years earlier by the Treaty of Shimonoseki of 1895 by which Japan appropriated the Liaotung Peninsula of Manchuria as one of the spoils of the Sino-Japanese War. Economic and political factors determined this demand for territory, and were in turn the progenitor of the vast program of continental expansion which has since been the basis of Japanese policy.

The diplomats, business men and publicists who were actively engaged in the penetration and exploitation of China during the latter part of the nineteenth century most frequently offered economic explanations for their actions. References to the commercial opportunities to be found in China appear with almost wearisome repetition in diplomatic correspondence, in treaties and conventions and in the press. Armed with a more complete knowledge of the situation, recent commentators upon European imperialism in China have been prone to discount this interest, and it is true that the China trade did receive notice that was out of proportion to its importance. However, the wisdom of hindsight may sometimes be misleading and unless we know the general opinion of the China market as it was expressed in the eighteen-eighties and eighteen-nineties the strong interest displayed both by governments and individuals in tapping that market is largely incomprehensible to us.

The first major schism to rend the inner core of the ruling group which had been in control in Japan since the Restoration in 1868, occurred in 1873 through differences of opinion over the proposal to send an expedition to Korea. For several years previous to 1873 there had been a growing demand, particularly on the part of the ex-samurai group, to make war on Korea. The dynamics, in this case, were neither obscure nor occult; they simply represented another example of the intimate relation which often exists between domestic policy and foreign policy.