We've said before that opening theory matters less than beginners think, and that's still true, most games below 1500 are decided by a hung piece, not a home-cooked twelfth move. But "just develop your pieces" is cold comfort when you're staring at an empty board wondering what to actually play. So here are six real answers: three openings for White, three replies for Black, each one chosen because it's sound, easy to understand, and forgiving when your opponent does something you haven't seen before.
As White: three openings that teach you chess while you play them
The Italian Game (1.e4 e5 2.Nf3 Nc6 3.Bc4). Every move fights for the center and develops a piece, and the bishop on c4 points straight at the weakest square in Black's camp, f7. Nothing here is hidden in memorized theory; the plan is visible on the board, which means the understanding you build playing it transfers to every other opening you'll ever learn.
The Italian Game after 1.e4 e5 2.Nf3 Nc6 3.Bc4. Three moves in, and White has already developed two pieces and aimed one of them at f7.
The London System (1.d4 followed by Bf4, e3, Nf3, Bd3, c3, and castling, in nearly that order no matter what Black does). Its whole appeal is that you play almost the same setup every single game, which means less memorization and far fewer nasty surprises than any opening that depends on what your opponent picks. If you hate opening prep, this is the opening built for you.
The Queen's Gambit (1.d4 d5 2.c4). It looks like you're sacrificing a pawn; you almost never are, and Black declining it (2...e6, the most common reply) leads to exactly the kind of classical center fight that teaches sound piece placement. Learning to handle an "offered" pawn calmly instead of panicking over it is a real, transferable skill.
As Black: three replies that hold up against anything
The Caro-Kann (1.e4 c6, planning 2...d5). The single lowest-drama reply to 1.e4 that still fights for the center. You get a solid pawn structure, no memorized forcing lines to worry about, and a position where good, patient chess beats memorized traps.
The Caro-Kann tabiya after 1.e4 c6 2.d4 d5. Solid, symmetrical-feeling, and nothing here requires memorizing a forced sequence to survive.
1...e5 in reply to 1.e4. The classical, symmetrical answer: develop your knights, get your bishop somewhere useful, castle, mirror the same Italian-style ideas you'd play as White. There's no shame in symmetry at this level; it's a promise that you'll reach a normal, playable middlegame where the better tactician wins, and that's exactly what your tactics training is for.
The Queen's Gambit Declined (1.d4 d5 2.c4 e6) in reply to 1.d4. The classical, low-risk answer to the Queen's Gambit: you keep your center pawn, build a solid structure, and never have to memorize gambit-acceptance theory to survive the opening.
You don't need all six at once
Pick one from each half: one White opening, one reply to 1.e4, one reply to 1.d4. That's a complete, sound starter repertoire, and it's plenty for years of improvement. The other four are there for whenever you get curious or bored, not because you're behind for not knowing them yet. Every one of these six lines has its own step-by-step lesson on Rookie, actual explanations of why each move is played, not just a list of moves to memorize and hope you remember.