The Japanese army wore the M1886 blue uniform at the beginning of the war, as described in the "China 1894-1900" section. Khaki uniforms were gradually introduced as the months went by. Reservist and artillery units, as well as some front line infantry, were still in blue when the war ended.
So I draw on my Japanese 1894-1900 army to provide the bulk of the troops for this army.
The khaki uniform is of near-identical cut. The only visible identification is now the hat band, whose colour depends on the branch of service (red for line troops, green for medical, etc.) Officers are distinguished only by their sabers and sober rank markings on the cuff, making them less conspicuous. The headgear has become more flexible (but this is unnoticeable at 15mm scale), and some soldiers wear a neckflap, to protect against the burning Manchurian sun.