My pen pal sent me an International Reply Coupon issued in Japan,But there is no Japanese postmark on the reply coupon. I am worried that China Post will refuse me to use the reply coupon for this reason.
The postmark of selling office is facultative, the important is that IRC Is still valid. Your post office will put its postmark on the coupon and give you the postage. I’ve tried using in Italy but it’s quite difficult due to absurd rules added by our Post on how to give the postage.
I used one once, but it was with the Portugese philatelic office, so I guess they exactly knew what to do. My advice would be to just try!
In my post office in Germany, this has never been a problem, I could always hand in reply coupouns without the postmark of the selling country. (And the IRC’s I have from germany have also no postmark of the selling office, and the recievers never reported a problem when handing them in).