1.e4 and 1.d4. Twenty moves are legal at the start and those two are the answer at every level from a first game to a world championship, for one reason: each of them puts a pawn on a central square and opens two lines at once.
What e4 and d4 actually do
1.e4 unblocks the bishop on f1 and the queen on d1 in the same move, and the pawn attacks d5 and f5. That is why the sharpest openings all start there. 1.d4 unblocks the bishop on c1 and the queen, attacks c5 and e5, and has the small extra virtue that the pawn on d4 is already defended by the queen.
The playing difference matters more than any evaluation. After 1.e4 the centre often opens by move six and somebody’s knight hangs. After 1.d4 the pawns lock together and the game is decided by which side gets a rook to an open file first. Play 1.e4 while you are learning. Tactics teach faster than structure.
The respectable rest
1.c4, the English, is a real opening: it takes d5 away from the black pawn and often turns into a 1.d4 game anyway. 1.Nf3 develops a piece to its best square and keeps every option open. Both are fine, and both ask more of you than 1.e4, because you have to know what to do when Black does something unexpected instead of following a plan you can see.
1.b3 and 1.g3 are playable. So is 1.f4. None of them are refutations of anything, and none of them are what I would give a beginner.
The two moves that actually lose
8
7
2
a
b
c
d
e
f
g
h 1
8
7
4
2
a
b
c
d
e
f
g
h 1 That is Fool’s mate, the shortest game there is, and it is the reason 1.f3 and 1.g4 sit at the bottom of the list. Even one of them on its own is bad: 1.f3 takes the knight’s best square away and weakens e1-h4, 1.g4 weakens the whole kingside before the king has anywhere to hide. 1.h4 and 1.a4 do not lose on the spot, they just do nothing, and doing nothing with your one free move is how you hand the initiative to Black.
And for Black
The answers worth knowing are 1…e5 and 1…c5 against 1.e4, 1…e6 if you want something solid, and 1…d5 against 1.d4. Which to pick, and why the Sicilian can wait, is on the best openings for Black page. Then go and play twenty games starting 1.e4 and count how many of them were decided by a tactic rather than by move one.