Most people are working hard and have no time to learn countless chess openings variations.
For them I introduce a system that I found by chance and is applicable for Black (or White) in every game no matter what White throws at you.
I will call it "The Universal System" but it is, in fact, a side variation of the Pirc Defence when White plays first move e4. If White plays 1.d4 or something else it may have other names, but who cares. Let's just call it the "Universal System" to keep things as simple as possible.
1. Black plays first move 1..d6 intending to establish a pawn at e5. Around this pawn the game will evolve in future, so make sure that your e5-pawn is always protected securely. 2. Black plays the kingside knight out to develop the kingside, but plays the queenside knight to d7 after that, to be able to PUSH THE e-PAWN ahead to e5.
The queenside knight at d7 has to go to c5 almost always. Don't let this knight sit on d7 because this is a bad position for a knight. You should move this knight to c5 as soon as possible after castling, in rare cases it goes to c5 even before castling. After this knight is developed the queenside bishop can move out freely...
As you can see above Black has established his e-pawn on e5 in all positions and supports it with his queenside knight d7.Study the Commented Game
We should go deeply into it, because it leads to tough positional play. However for a start get the idea and just replay the games below and assume that you are Black.
Get this: You can use this opening if you have the white pieces as well. This way you are one move ahead and can apply the knowledge that you have gained while playing this opening as Black. This way you will save a lot of time in opening preparation.