It is believed that about 80 000 Russians were captured in the Russo-Japanese War of 1904-1905. The biggest POW camps were located at Osaka (25 000 POWs) and Narasino (15 000 POWs).
Russians were well treated, able to write and receive mail, able to worship, had entertainment facilities, and were paid a work allowance. Officer and other ranks barracks were also maintained. Some of them even got a specially created silver medal (I think more correct name for this award will be a “token”). It was awarded to heads of barracks and prisoners that demonstrated “good conduct”.
For obvious reasons this medal is pretty rare.