Which chess opening to learn? I decided to start learning some opening theory, so far I have only played online and studied a couple of end games. Seems that a correct approach might be to chose one opening for white and two for black (answers to e4 and d4), and stick to those three openings for a while, since that is a fairly low number so you can keep up with the variations with some work, and also large enough so you can use your preparation in a good amount of games.

So the question would be, what do you think is easier to start with, as a first timer learning any theory, e4 or d4? (I usually prefer d4 for no particular reason). And which defenses would you start with against those two moves as black.
For a beginner, the goal of the opening is simply to avoid losing material and blundering; don't stress playing a perfect opening just yet. However, here are some general (and not at all exhaustive) distinctions between the openings:


e4


Often leads to open games
Bishops are slightly more valuable, as they have more space on the board to play
Through the midgame towards the endgame, entire files may be left open - because of this, Rook positioning is key and often can be make or break
Openings to study: Ruy Lopez, Sicilian (although I'd avoid playing the Sicilian as a beginner)

d4


Often leads to more closed games
Bishops and Rooks are relatively immobile throughout the midgames, and serve passive (but still important!) roles
Knights form the basis for strong attacks and exerting control in the center of the board
Openings to study: Queen's Gambit, Indian Defenses (fianchettoed bishop)



Ultimately, you should decide which you prefer better. However, I personally find 1. e4 to be a simpler opening to play, with less chances for blundering. Hope this helps!