In the WW1 the Japanese where lenient towards POWs. Allowing them to take hikes, visit villages and even put on orchestras. In WW2 Japanese POW camps where notoriously brutal (only rivaled by German death camps and Soviet Gulags). What changed between wars ?

by Garrus37
Georgy_K_Zhukov

More can always be said, but this older thread has several responses you might find of interest.