glad you asked. i never researched it much till now. i found it on wikipedia. it is a Japanese government-issued Philippine fiat peso. its part of the 1942 series. they printed tons of occupation notes. lots of it never went into circulation. so its not uncommon to have crisp ones like the one i have. but lots of it was destroyed due to it being worthless after the war. so its not super rare but its a piece of paper that survived WWII and is now 70 years old. so its still a cool collectors item.