Early on in this discussion, War Hymn, you asked about "Japanese Pesos." Don't know if that was answered or not, but those come from the Philippines. When the Japanese occupied the islands in the early part of WWII, they took the existing Philippine currency, the peso (a legacy of Spanish control) and made new ones.
The writing on them is in English because then (and now) most Filipinos speak English as their primary language. A lot of Americans in WWII who served over there scooped up those bills, which became worthless after we took the islands back from the Japs in 1945. I have some of these myself, and they should say something like "Japanese Government" on the top.
[This message has been edited by aalan94 (edited 10/31/2013 1:56p).]