From The Anguish of Surrender: Japanese POWs of World War II, by Ulrich Straus (U. Washington Press, 2005), pp. 19-20:
During the Sino-Japanese War of 1894–1895, Japan stated that it would abide by the Brussels Declaration on prisoners of war, the first such international effort to regularize and humanize the reciprocal treatment of POWs. In that conflict, the Japanese captured 1,790 prisoners, while only one Japanese soldier was taken prisoner by the Chinese. Japan treated its prisoners humanely.
The Hague Convention of 1899 on the treatment of POWs was operative during the Russo-Japanese War of 1904–1905 and was generally observed by both sides. At the end of the war the Japanese held 71,802 prisoners, while the Russians had captured 1,626 Japanese soldiers and sailors, including 26 officers. The Japanese government of that time, unlike the one during World War II, acknowledged the existence of Japanese prisoners in enemy hands, including a regimental commander. Japan even sent a request through the U.S. government, which represented Japan’s interests in Russia during the war, asking that conditions be improved for Japanese POWs in Russian prison camps. It also facilitated the sending of letters and packages to Japanese POWs through international Red Cross channels. In line with this willingness to acknowledge the status of its captured military personnel, a regulation of Japan’s POW Information Office at that time stipulated that the name, rank, and other information of each POW would be published when received. (This regulation was voided on December 27, 1941.) Japan and Russia also agreed to several exchanges of prisoners while fighting was still going on.