Issued for the Japanese occupation of Malaya. You may encounter information that says they were for a planned invasion of the US but there is not truth to that.
Japan issued currency for several Southeast Asian countries in WWII - including the Philippines. Most of them have little value, since they were issued in countless numbers and weren't used too much at the time. After the Japanese lost control of whatever country they tried to occupy, the money became worthless and was often seen littering the streets. Amazing piece of history, however. I have a bunch of these from different countries and I really enjoy them.
