In 1918 there was a need of a 27 Øre postage stamp. The rate was used for registered letters to Sweden and Norway.

The mail services had a large amount of old stamps, which were not used anymore. The stamps were overprinted with this special value.

In 1918 - 1920 the stamps with king Christian X. became two-colored. 7 Øre and 3 Øre became printed printed together for making a couple of stamps for stamp machines.

Commerative Stamps

Until 1920 Denmark had never issued commerative stamps. To celebrate the reunion of Slesvig, Denmark issued a little series of stamps showing a few famous buildings around the country.

The 10 Øre value is showing Kronborg Castle, the 20 Øre value the castle in Sonderborg, and the 40 Øre value is showing the cathedral in Roskilde.

The first Danish stamps with a surplus were issued in 1921. The surplus was for the Danish Red Cross.

Special Stamps

In 1923 special stamps were issued to make a receipt for special duties done for the costumers by the postal offices.