Tarrasch against 1.d4, because kids misplay everything else.  They'll get blown off the board without central pawns as in the QGA and Grunfeld, if they play a QGD they'll never activate their light-squared bishop, etc.

Hello,

In our club we have been teaching chess to some kids after their normal school classes. Some of them are starting to compete in local tournaments against other kids of other schools or other cities near us. 

Everybody plays 1.e4 at that "levels". And we are focusing on quick piece developments, open games, basic tactics, etc... As white, Italian Game of Ruy Lopez. Plus some basic ideas against Sicilian, Scandinavian, French, or CaroKhan.... But 80% of the games are 1.e4 e5 with both colors. Zero theory right now, only ideas, of course.

But what against 1.d4? As they are becoming better and they play online at home or against a better prepared opponent.... Which opening would suggest to start with? My initial though would be Tarrasch Defence, easy to learn, tend to open games and sound; for me in terms of practicality is the better option (1...e6 2...d5... 3...c5 against anything but 1.e4). But other people here thinks that slav or QGD are better options.

What do you suggest us as a starting point and why? Tarrasch? Maybe another option? 

thx !

Excuse me if there is another thread asking this...