What In The World Is An ''open Letter?''

Hello all!

I have a cover that I was told is more scarce due to the fact it was considered to be an open letter and thus was mailed for the rate of a postcard rather than a letter which was cheaper. Could anyone maybe enlighten me as to what an ''open letter'' is? My friend who gave me the info above is not available to answer my question and I figured the wonderful members of stampcommunity.org might be able to help!

thanks!

A picture would be helpful.

What you likely have, to use U.S. terminology/classes/rates, is a piece of 3rd class mail, which was sent unsealed, and thus went for a lower rate. While the rate may have matched the postcard rate, it was an entirely different class/type of mail. 3rd class mail is typically "junk mail", advertisements, etc., which has a low survival rate. So while less common that 1st class mail, its monetary value depends on the totality of its "postal history" factors.

In the UK, before the introduction of first and second class rates in the 1960s, unsealed letters were cheaper and widely used, eg for Christmas cards.

here's the cover it's bulgarian as I said it was supposed to have 7+5 7 for the letter and 5 for airmail to germany but its 4 +5 4 for a postcard and 5 for airmail to germany

One clarification. It is *not* a postcard, so it is *not* being sent at the postcard rate.
It might be sent at a discounted letter rate, which by coincidence may happen to be the same amount as sending a postcard.

On another tangent ... is it possible that your associate means "open letter" to be opened for censorship, noting the sealing tape along the left edge of the cover? And that the cover was sealed normally by the sender and slit open during transit for inspection. A nice squared-up image of the reverse might be helpful, outside the plastic protector to eliminate the glare.

Can this have been sent at either the 'printed matter' or 'trade sample' concession rate?

NSK,
I agree, it does look like it is going between 2 companies, so it might easily contain printed matter such as a price list. Each country has its own rates/regulations on such mailings.
I never imagined this being from Bulgaria when the first post was made.