An Austrian museum association has asked its Twitter followers to help deciphering an old postcard. So far, no solution has been tweeted. Can a reader of this blog solve this mystery?


In 1905 a certain Miss Rhodes from Colchester, UK, received an encrypted postcard signed with “C.Y.K.”. Can you decipher it?


A Reddit user has posted a postcard from Sweden written in 1910. Can a reader decipher it?


Here’s a postcard that was sent from the Isle of Wight to London in 1905. Can a reader decipher it?


In 1901 an unknown person sent an encrypted postcard from Iserlohn, Germany, to nearby Arnsberg. Can a reader decipher it?


A postcard from 1903 is encrypted in a dancing men code, like it is described in a famous Sherlock Holmes story. Can a reader decipher it?


Here’s a postcard written in English that contains two kinds of encryption. Can a reader decipher this two-part cryptogram?


Here’s another crypto postcard. As the encrypted part of the message has only 17 letters, it is probably hard to decipher.


In 1909, an unmarried woman in Newcastle, Australia, received an encrypted postcard. Can a reader decipher it?


Only three of the many encrypted postcards I have covered on this blog so far have remained unsolved. The one I am going to introduce today might be number four.