[A "civilian" Japanese coolie in rain gear, ca 1885. The pole was used to carry heavy burdens hanging on the two ends, and the whole load balanced on one shoulder.]
Japanese transport coolies who accompanied the troops to the front line as Military Laborers [軍夫] were supposedly non-combatants who simply provided the much needed logistical support. This was generally true; although they did volunteer to fight, e.g., in the previous sacking of 大連Port Arthur in Nov, 1894.
In fact, even though it was never mentioned in the history books, Japanese 軍夫 did commit violent acts against the Taiwanese during the Japanese invasion of Taiwan in 1895. James Wheeler Davidson (1872-1933) had hinted at such in his 1903 book "The Island of Formosa, Past and Present"; London and New York: Macmillan & co.; Yokohama [etc.] Kelly & Walsh, ld. [The full version can be found here: http://www.archive.org/details/islandofformosap00davi]
On pages 341-2, he wrote:
...It was not considered politic to depend entirely upon Chinese, although they had so far been found satisfactory; so Japanese coolies were brought into the island in numbers sufficient to completely equip the expedition. Japanese coolies accompanied the Imperial Body Guards [i.e., the 近衛師團] when they first arrived in the island, and whether they were then more carefully selected or were under better control I do not know; at all events they made no trouble. Also the soldiers of the guards seemed to be polite and gentlemanly, quiet, and good humored, and many well educated young fellows were among the privates. I was with them on and off for three months, and the conduct of officers and privates was such that I became enthusiastic over their general good qualities. On my return from the south, I found a decided change for the worse. Scenes of violence, approaching to ruffianism, took place in the streets. First, there appeared to be a deplorable change in the character of the soldiers. One saw among the new arrivals many who were rough, uncouth, insolent, and disagreeable. They, of course, formed but a small part of the whole; yet they were sufficient in number to lower the reputation of the service to which they belonged. Chinese are adepts in acts of foolishness, and often give cause for much irritability; yet there was but little forbearance shown them on the part of some of the soldiers. My experience with the Japanese troops in the field leads me distinctly to disbelieve the tales of wholesale slaughter reported by the Chinese, which occasionally reached the columns of foreign journals. The troops were then marching in large numbers under the control of their officers, who were educated and enlightened men. There is no doubt that occasional excesses occurred; for soldiers, whatever be their nationality, are far from immaculate; but the injury to Japanese reputation thus caused was small compared with that worked by the coolies, individual soldiers, and the lower class Japanese, in the thousand little acts of harshness and abuse towards the Chinese during the period of occupation. Much as I respect the Japanese people in general, I must admit that the coolie class, as I encountered them on the streets, in public places, etc., were inferior to the Chinese coolie of Formosa in general bearing, in cheerfulness, and in politeness to strangers. I say "of Formosa;" for I do not wish to convey the idea that the coolie, as seen in this island, was a representative of the large mass of laboring men in Japan; in fact, so striking was the difference that two English gentlemen, both of long experience with the Japanese of all classes, informed me that they could not have believed that there was material in Japan from which to draw such a class, had they not witnessed their ill-mannered conduct with their own eyes. The reader should also understand that the Chinese in Formosa have of late been very friendly to foreigners and are more liberal-minded than the mainland Chinese; in fact they show none of the hostility to strangers common in some districts of China. Therefore, it would not do to extend this comparison either to Japan or to China. On the part of the military administration, whose whole attention was directed towards the completion of the occupation of the island, but little attempt was made to curb the high spirits of the Japanese coolies. It is true that the poor fellows spent a good deal of their time in the various hospitals, and large numbers found a grave in the island, and we should perhaps take into consideration the arduous labor in which they were engaged in a country not their own; with but scanty food ; often forced to sleep in the open fields, and exposed to an intense heat to which they were not accustomed. Again the Chinese often thought they were ill-treated when they were not. Military rule is in many ways unpleasant, but is the same in that respect all over the world. If the necessity should again arise for the Japanese coolies to be made use of in military operations, some provision should be made to place them under more strict control than they were under in the expedition in question. One can scarcely blame the better class of Japanese for not having come to the island during the early days of the occupation. Quarters were few and miserable, and disease was attacking large numbers. During the latter part of August, the three government hospitals in the north of Taipeh, Kelung, and Teckcham [note: this was 竹塹, the present-day Hsin-chu] received nearly 2,000 patients, and deaths were occurring at an average rate of 18 per day...
For a somewhat pro-Japanese westerner, Davidson did tell us the ominous change in the quality of some soldiers and, more important, the "thousand little acts of harshness and abuse towards the Chinese [i.e., the Taiwanese]" perpetrated by the lowly coolies. To the Taiwanese, there was no distinction between Japanese coolies and soldiers; they were all ruffians, or worse. Davidson himself probably was unable to differentiate between these unruly coolies, individual soldiers, and lower-class Japanese. And apparently the high command did not attempt to reign them in, either. These criminal acts no doubt had further fueled the Taiwanese resistance when the Japanese marched and attacked south. Despite Davidson's initial disbelief, many villages in southern Taiwan even now still bear silent witnesses to the atrocities committed against their residents. In all, about 14,000 Chinese soldiers and 100,000 Taiwanese civilians perished in the 10-month 乙未 war.
In the end, Japanese coolies did not fare so well in the Taiwan campaign. They died in the hundreds from diseases [possibly cholera and the mosquito-borne malaria] and exposure. Their deaths were excluded from military casualty records and were apparently forgotten.
As if heeding Davidson's advice, the status of 軍夫 was elevated in the subsequent foreign wars to almost that of the modern combat service support. The indoctrination was for all Japanese nationals to sacrifice for their emperor; becoming a 軍夫 was therefore a great honor and an important opportunity for this cause.
Starting in 1942, Taiwanese youths were officially drafted to serve as 軍夫 [and also as 學徒兵 and the higher ranking 軍人 and 軍屬]. These were the well-educated men with most of them from middle-class families. And to drive home the point, many prominent Taiwanese were also asked to serve as 軍夫. The song, the Honorable Military Laborer 誉れの軍夫 (1938), adapted from a popular Taiwanese ballad 雨夜花 (1934), became the call to duty:
赤い襷に誉れの軍夫 うれし僕等は 日本の男
[Wearing red sashes as a honorable military laborer, we are the men of Japan]
君にささげた男の命 何で惜しかろ 御国の為に
[I'll dedicate my life to the Emperor and unreservedly to the country]
進む敵陣ひらめく御旗 運べ弾丸 続けよ戦友よ
[Rushing into enemy lines waving the royal banners and transporting ammunition to my comrades]
寒い露営の 夜は更けわたり 夢に通うは 可愛い坊や
[Lying on the cold camping ground in the middle of the night dreaming about my loved ones]"
花と散るなら 桜の花よ 父は召されて 誉れの軍夫
[If a flower is to wilt, let it be the cherry blossom - I call on my dear father, the honorable military laborer, to be so]
And they joined up in great numbers and were sent off to the Pacific War. Essentially, in less than 50 years, a whole generation of Taiwanese was transformed into loyal Japanese - only to be abandoned in 1947 when Japan revised its 戶籍法Household Registration Law that disowned non-Japanese nationals, including the Taiwanese. This generation now in their 80s is still with us today.
And the song 雨夜花 is still with us as well. The video below shows a recent rendition of the original, composed by Mr 鄧雨賢 (1906-1944) with lyrics by Mr 周添旺 (1910-1988), performed by 江蕙 and in the second part by Placido Domingo et al on Nov 28, 2002, in Taipei: