The idea of the national sides of the Euro coins is to allow the various countries to present their own cultural identity.
The countries have a great deal of freedom in the design of their national sides but there are overall recommendations/guidelines that should be followed but are in fact often not adhered to.
The original guidelines were that the national side was not to indicate in any way the country issuing the coin - a difficult recommendation to understand - as are many decisions emanating from Brussels!
At any rate only four of the Euro States (Belgian,Finnalnd, Germany and Greece) adhered to this guideline. The others, in various ways, circumvented it - Portugal ,as an extreme case, has the full name appearing twice! whereas Italy for example restricts itself to RI (Repubblica Italiana) - details of all these violations appear on the sides dealing with the individual countries.
In 2005 it was decided, in a complete about-face that the national sides should indeed contain a clear reference to the issuing country - now those who had stuck to the guidelines had national sides that deviated from the rules and those who had violated the original guidelines had national sides that accorded with the new regulations!
The ways of bureaucrats are not always easy to fathom!
Other decisions that were made in 2005 were:
a) that the 12 stars representing the EU (European Union) should appear as in the European flag - i.e. in a full 360° circle. A few countries e.g. Holland do not conform in this respect.
That the value of the coin should not appear on the national side
unless the country did not use the Latin alphabet - so at the moment
Greece and Cyprus do not have to conform and possibly in the future
Bulgaria will be exempt. If there is a rational reason for this decision
it is unknown to me.