After the Japanese Tanaka Detachment landed at Aparri and Gonzaga on December 10, 1941, they occupied the capitol and it's adjacent airfield. In the meantime, the Philippino Governor of Cagayan Province had evacuated his Provincial Government to the isolated municipality of Tuao. Due to a shortage of currency to pay for necessary expenditures he created a Currency Board on January 1, 1942 to try to solve the problem. The result was the printing of four separate issues of Emergency Currency.
The first issue from this province is actually comprised of Postal Money Order forms (with serial #'s recorded for later redemption). More info as I get it.
Second issue notes were mimeographed forms, folded in half and glued together with silk thread layd out inside, with an Internal Revenue stamp of the appropriate denomination applied to it (on the left side of the obverse).
The third issue was actually a continuation of the second, consisting of a couple hundred 50 centavos notes with a facsimile "war bill" stamping applied where the Revenue stamps had been applied. This was done once the real stamp supply had been exhausted.
The fourth issue was printed from hand engraved lead plates made from melted down lead from car batteries. The ink that was used ranged from duplicator ink to diluted house paint, with over- or under-inked notes very common occurences. Almost any type of paper that they could find was used to print the notes. Serial numbers on the reverse were all hand written.