Why should series be limited to one issuer?

The guideline for both coins and banknotes say:

• Series names should be unique for a given issuer.

What is the reason for this constraint on series? If two issuers coordinate on a set of coins shouldn't they be in the same series?

And even if two issuers don't coordinate but if they commemorate the same event shouldn't the same series name be used. Several countries issued coins commemorating the 70th Anniversary of the Battle of Britain – should there be a separate series for each issuer with the issuer name in the series name.

Two current examples which I believe are appropriate:

• FAO coins.
• Erasmus Programme two euro commemorative coins. (And other Eurozone wide sets of related issues.)

One example I think should be used for multiple countries: 70th Anniversary of the Battle of Britain.

I read it as that in one issuer you shouldn't have the same name for two different series like Olympia instead ‘Olympia year 'xx’ and ‘Olympia year 'yy’.

You often can write a sentence in English and read it in opposite ways.

Idolenz

I read it as that in one issuer you shouldn't have the same name for two different series like Olympia instead ‘Olympia year 'xx’ and ‘Olympia year 'yy’.

You often can write a sentence in English and read it in opposite ways.

OK. I'll assume it isn't meant to exclude cross-issuer series. But the intent should be clarified (or the sentence removed).

I don't like your suggested restriction. There are currently series for each Olympics and I don't  think they should be combined. (But the series names for Olympics should be more consistent – I'll put that on my cleanup list.)

Ones worth mentioning are Winter Olympics, FIFA World cup, liberation/independence of countries and large scale conflicts (Napoleonic Wars, WWI and WWII).

My Olympia was a negative example … how you shouldn't do it. They should be unique like written in the guidelines. aka split into the different years.

Hello,

I confirm series can extend to multiple issuers. This sentence of the guidelines is to avoid having multiple different series sharing the same name.

I adjusted the sentence to make it more explicit:

• For a given issuer, series names should be unique: two different series of the same issuer should not have the same name.