The end of arrival stamping in Finland

Arrival stamp is the cancellation that a letter would get once it enters the target post office and before being sent to it's respective receiver. Before 1964 in Finland all letters - regardless of their classification - would be subjected to arrival stamping. Arrival stamping became mandatory in Finland in 1858. However, arrival stampings of 1857 are known exist. In the early days these stampings were solely in the form of ANK-cancellations and later on (in the 1888 to be exact) their use was forbidden and post offices would have to start using their regular cancellation stamps as arrival stamps. However, ANK-cancellations of later dates are also known.

Postal authorities in Finland in the 1960's had observed that many other countries were stopping this procedure to cut costs and followed suit starting in 1964. The first step was to stop arrival stamping from being implemented for only regular letters and this was at least partly successful in as early as 1965. This practise was gradually extended throughout the country in the following years. 

Later in 1978 the rules dictated that registered, express and insured letters must still receive their arrival stamping. Just a few years later in 1981 even registered letters were dropped out from this list. There isn't a hard-coded listing of exact dates after which letters would no longer receive an arrival stamping. 

This information is something to consider when analysing mail and possibly spotting out anomalies or even obvious forgeries. The rule of thumb, however, is that every letter sent being addressed to a Finnish address before 1964 should absolutely have an arrival stamping as the process was mandatory. Accidents of course did happen: letters would get stuck together and only the top cover of that stack would receive a stamping or perhaps the cancelling device had run out of ink and did only produce a faint or non-readable stamping on the cover.