Help Understanding Ca. 1900 German Postcard

Hello, I picked up this piece a while back and am a bit confused.

It appears to be two German pre-printed postcards dating to 1900 or after that are connected. The inside postcard has an address and is cancelled, so was sent through the mail. The attached postcard (on the other side of the blank section in the first image) has no address and is not cancelled. I am not certain what this is or how it went through the mail. Thanks for your help.

It is a reply card. It was sent folded. The first card was canceled on the journey from Leipzip to Iburg. The recipient would normally separate the two cards and send back the second half (antwort = answer/reply), but they did not do so. This was a way for the original sender to pre-pay for the return message. The U.S. also has reply cards.

Hi,

This is a reply card and was a standard format at the time.

The original sender paid for postage for both the original card and the attached reply card when he bought the cards.

The sender here appears to be a music publisher from Leipzig and he has filled in his return address on the return card (identified with the printed word "Antwort" = Answer) but the card was never sent back.

This card was sent to Iburg in Germany but you also got international versions at a higher rate and these could be sent back under UPU rules with the postage fully covered by the appropriate imprinted German stamp.

Thanks for the quick answer. That is a fascinating (and clever) way to try and get correspondence returned.

The original postcard was from a music publisher (there is a note on the other side of the cancelled card). I collect music-related psotal material and this was something that caught my eye, even though I wasn't sure what it was. Thank you much.