The visa that was opened for entry into one of the countries of the Schengen area is valid for any country that signed the corresponding agreement .But if it is a question of a single entry visa, you can enter the Schengen area only through the country to which the visa is issued..In this case, if you, for example, have received the Estonian Schengen, then in any country you can get to only if the first visit to Estonia is .Even if you have a multiple entry visa, the country of first entry should still be the country whose embassy issued this visa .This restriction does not apply only if you travel by land, because to get to the country that issued you a visa, it is necessary to cross the borders of other countries in the way .Pay close attention to this in details..This is important, as recently in all countries of the Schengen agreement the "first entry" rule has become tougher: if you are caught in its violation, this incident can create serious problems for you in obtaining a visa in the future..