@aerobear Oh weird, I looked again and one of my postcards has it as the last three of the zip code 
another the first three, from confirmed addresses. Maybe itās cause one is older?
@monarja if it smells citrus like you might have invisible ink 
1 Like
Hurrey, guess what. I got hint from you that it might have invisible ink. Well I examined the card in bright light at some angle. And I could read the card ID, and senders message. So the mystery is solved. Thank you all for your inputs.
38 Likes
so did the mail carrier have an uv light to read it or what have happened?
Can it be itās made by Frixion pen, as some say, it disappears in too hot or cold?
Or, a glued message and address, and you can see the traces of pen?
I would never dare to use invisible ink to the address part.
2 Likes
Omg congratulations, 
1 Like
I guess the postmarks are more of a mystery to me than I realized!
Wow thatās cool! Congrats on receiving such an interesting postcard!
1 Like
Ha, Mumbai ,where the dabbawalas always deliver the right tiffin to the right placeā¦
Yes, you are right. However due to lockdown since march most of offices are now working from home and so these dabbawalas have lost their livelihood, as no tiffin to deliver.
2 Likes
Another internet mystery yet to be solved!
One time, I received a postcard with another postcard stuck to it. My address showed on the āfrontā but someone elseās postcard was the āback.ā I separated the two, logged both, and then sent the other card on its way-- in an envelope this time. I wonder if this might have happened here-- that the original addressed card fell off. But how it ended up in Indiaā¦?? A delightful mystery!
How very sad 
So there was an address after all, or just the ID and message?
I believe the ā00174-0001ā in the barcode is just one of many USPS sorting codes for international mail. It does not correspond to any postal code but is just a country code or something like that. It does look like an Italian post code for the Rome area but Iād highly doubt it. Maybe Postcrossers outside the USA can look at the codes printed on cards from here?
Three things come to mind. There was a label that hung on just enough for your postman to see it. Or, a label that hung on just long enough to get to his carrier office. Or third, your postman knows you are a Postcrosser and just assumed the mystery card with no address, regardless of what serendipity brought it there, was one of yours.
3 Likes
That is such a tragedy! So many hundreds of thousands, maybe millions of job losses.
Makes me think there must an Island of Lost Postcards somewhere (like the Island of Lost Toys in Rudolph the Red-Nosed Reindeer) where many of our postcards go - some stay for a while & then leave & others stay there forever.
I wonder about all the stories of both those postcards who get to leave & those that get stranded. I wonder about the mysteries of how they get there & what happens so they can leave. I wonder what they talk about while theyāre there eh?
2 Likes
I am an American living in Canada, so I get a fair bit of mail from the US. The code at the bottom is always 00299-2300 on mail from the States, which I suspect must be Canada or even Ontario, Canada. Iāve always wondered what the code actually means.
Maybe we could gather these all up from around the world and start a new thread?! Seriously though, there must be some meaning behind these numbers, but the USPS isnāt saying. Here it looks like that must the code for Canada or maybe just part of it. I wonder what other Canadian Postcrossers have seen? It also wouldnāt surprise me if it might vary from where in the US one sends it from.
1 Like
I got a postcard the other day that was for my neighbour. I think the Postman is so used to me receiving them he didnāt even check the address.
5 Likes
This post (and the thread more generally) has some good info re sorting codes
@monarja This is absolutely fascinating, thank you for sharing this! I really do believe the worldwide postal system is a miracle sometimes 
Edit to add: WOW, I just looked up the card on your wall and realised this invisible card was delivered to you in SIXTEEN DAYS. I donāt think Iāve received even a single standard card, completely legible and properly addressed, that quickly! Some champion work from the postal system, I think!
1 Like
I did some googling and these numeric codes are USPS International Mail POSTNET (Postal Numeric Encoding Technique) codes that are used internally by the USPS to direct mail to the proper international port. This link has a list of POSTNET codes corresponding to countries. India is 00174 and Canada is 00299. The list is from 2009 and it looks like the codes are updated every few years.
USPS also has a tool to decode the Intelligent Mail barcode. The resulting information is just a series of numbers like service type, mailer id, serial number and delivery point code.
3 Likes
Wow! Thanks for the links. I never even thought to research it further. Nobody I knew at USPS had the slightest idea beyond āthat information is proprietaryā and I never really cared to research it further after that. Iāve had customers ask me from time to time and my boss told me to mind my own business, so that didnāt give me any incentive either. I never knew it could be so fascinating. Now Iāve got some reading to do. Life is a never ending learning process!