Help Needed On Overprint/Canc Selangor Stamps - 1936; Japan?

Hi All,

I like a bit a philatelic detective work but I'm afraid this item has me beaten. It was at the bottom of a shoe-box lot I picked up 30 years ago and I've just come accross it again, during a classic my-partener-dosesn't-understand clearing out session.

I've enhanced the contrast on the stamps to try to highlight the overprint (it might even be just a cancellation). It doesn't look like a Dai Nippon; it looks too square. I've also included the little message which was written on the back of the fragment as it makes me smile.

This ebay seller has a green 3 cent (PB1710B) version here: http://www.ebay.com/itm/MALAYA-P171...em58c4e375ad

This ebay seller has a brown 10 cent (PB2010B) version here: http://www.ebay.com/itm/MALAYA-P201...em58c4e37e3b

Maybe some of the seller's descriptive information will help

UPDATE: This appears to be very similar to your picture above for the 5 cent: http://www.ebay.com/itm/I-B-Malaya-...3&rmvSB=true

Many thanks for the input. The third link seems to be the same and "Revenue" appears to be the magic word. That would explain the lack of postal cancellation and the fact that my old Gobbons Commonwealth has nothing.

I've found a coulpe of other examples on Google but I'm still not sure if these are Malayan Reveune OP on postal issues merely used during the Japenese Occupation or if they're Japanese revenue OP used on Malayan stamps.
Again, many thanks, Oldguy.