Hey buddy, I think you need to focus more on tactics, checkmate patterns and basic endgames! Worry about opening theory later. Wish you the best.
Learning opening theory

To answer your question, just stick with a few openings at first and try to understand them by learning its ins and outs, rather than just memorizing all the variations at once, because that would just give you a headache, lol.

i am 1000 in blitz, and i lose lots of time during the opening. i am currently reading a general middle game book,and an endgame book. the 4-5 last games i played ( lost 1 though) , i was in a resign mood after about 10 moves,cause i was really wasting my games. but each time ( almost), i could retrieve a bit of oxygen during the middle game, and win brilliantly (in a sense of a 1000 rate of course) in the endgame. only 1 i lost during my tonight session was a game i adventured myself in a sicilian. i really feel me too that the first phase of the game is what gives me a lot of frustration. i m going too to start studying opening ideas ( though, i already always focus on the general idea my openings, like fight for center, gain a tempo to be able to develop faster etc...). i feel the general belief of beginers must focus on tactics is true but limited. chess is an overall skill game on which your strenght of your play is limited by the part of the game where you are the weakest imo

Hi Chess.com community. I wondering if any advice can be shared on opening theory. Im at 1300 and i realised that if i learn opening theory it will help me alot. Anyway, how should one go about learning the theory - Do you just have to write out every possible variation and memorise it or is more important to understand each variations position. If its just brute force and memorisation then how deep should I learn each variation ?
Thanks
Friend
I just play unorthodox openings constantly, and buy a couple books on them. I'm still young enough to memorize them whether I like to or not
It's important to understand the opening ideas for the ones you're playing. For example, if you have a fianchettoed bishop, you usually want to "extend" its range by removing enemy pawns from its reach.
Knowing a lot of lines in openings comes from experience, not just memorization. I find it harder to pick up new openings now, since I automatically play my "usual" defenses/openings before I realize "Oh, I wanted to play x opening!"
lol.

Im at 1300 and i realised that if i learn opening theory it will help me alot.
You play only blitz which won't help you improve, and also learning opening theory won't improve your play.
it will
in bullet

Hi Chess.com community. I wondering if any advice can be shared on opening theory. Im at 1300 and i realised that if i learn opening theory it will help me alot. Anyway, how should one go about learning the theory - Do you just have to write out every possible variation and memorise it or is more important to understand each variations position. If its just brute force and memorisation then how deep should I learn each variation ?
Thanks
Youre rated 836 in daily chess.
All you play is speed chess.
Openings are a waste of your time. How are you expecting to improve when you're moving fast?
How exactly are openings supposed to help you stop blundering, and missing simple tactics?
Memorizing openings without understanding the "why" behind the moves will lead nowhere.

Hi Chess.com community. I wondering if any advice can be shared on opening theory. Im at 1300 and i realised that if i learn opening theory it will help me alot. Anyway, how should one go about learning the theory - Do you just have to write out every possible variation and memorise it or is more important to understand each variations position. If its just brute force and memorisation then how deep should I learn each variation ?
Thanks
It is NOT brute force memorization lol Even modern day computers can't do this! This is why you can see Stockfish, AlphaZero, Komodo and others "calculating and evaluating." Even if chess computers already knew which lines were "best" (an incredible feat on its own), then the amount of memory even required to store all of this information would be too massive. Perhaps you can look up Claude Shannon and the Shannon Number if that interests you. Shannon was a mathematician (among many other things) who calculated that chess has about 10 to the 43rd power legal chess positions (Shannon Number). This is a "1" with "43" zeroes after it! No way a computer could store that much with our technology (and I don't see it reaching it anytime soon if ever) and certainly too much for a human player to memorize. Plus, this is only for legal chess positions. Memorizing opening lines, transpositions and all would be a way higher number for sure! So yeah, definitely not only memorization.
Now with that said, you are correct that it is "more important to understand each variation [from the mainlines to the branching sidelines]..." The key to learning openings has a lot less to do with sheer memorization and more to do with learning thematic motifs and plans to that opening in addition to understanding the position, pawn structures, and other important factors.
I have mixed feelings about learning opening theory though - especially at 1300 or so. Many successful players don't really begin to study opening theory (really study it I mean) until at least 2000+ rating and some would argue it is closer to 2300+. Most players will just brush off the beginning chess player and tell them to work on tactics or endgames etc. Those things are certainly more important than opening theory, but I don't think this should be an excuse to know absolutely nothing about opening theory either - just that you don't need to actively study it in close detail.
I would say by 1400 or so, players generally at least know their own openings by name and know the first 4 or 5 moves of opening theory, but little else exact after that. Maybe they know one or two thematic motifs and that is all they need. For example: the King's Indian Defense almost everyone knows the start of this popular opening. Most Black players know the thematic idea of going for the ...f5 pawn push; that is about all the earlier levels need to know though! Keep it simple because your opponents probably will not follow exact opening theory at this level anyway, so study of exact lines would just be a waste of time (or at least not immediately beneficial).
I would say by 1600 or so, most players seem much better rounded. They probably know all the basic endgames and checkmates by this point as well as the basic tactical patterns. This is the stage I think most start to look more towards opening theory, but for "real understanding" of opening study, I think this is too early for sure. Depends what "opening theory study" includes though. I expect a 1600 player to know most or all of the mainlines/sidelines to their main opening(s) for at least 4 or 5 moves or so, but anything more is too rare quite frankly. Their opponents probably still will seldom follow these exact lines. This is why it is more about ideas and patterns in chess - not brute force memorization.
I know I posted a fairly long response, but I want to give an honest answer and not brush off the op due to current rating. I believe that learning a little about openings might help, but there is a good chance you won't use any of this knowledge for a while; there are certainly more important parts of chess to study: but if you feel motivated to get a taste of opening theory: then I say go for it! Just understand that you won't be changing your opening repertoire because your line scores lower in some sideline on move 12 or something: that is "real opening theory" and probably isn't relevant until the level when your opponents also play those lines exactly. How strong would this be? 1800? 2000?2300? Maybe even grandmaster ability? Partly depends on the opening and how deep you are going with it.
p.s. I'd be happy to discuss a little opening theory if you like (specifically the op, but also for others curious), but it probably isn't going to be what titled players are doing with opening theory.

Chess Openings Resources for Beginners and Beyond...
https://www.chess.com/blog/RussBell/openings-resources-for-beginners-and-beyond

You should know the key ideas of the openings you play - and which moves allow you to use these ideas. For example in the French advance (1.e4 e6 2.d4 d5 3.e5), if your idea is to put pressure on the square d4, you will have to know the moves c5, Qb6, Nc6, Nge7/Nh6 and Nf5. Knowing the basic move order is important, but in this example, after the move 6 you can continue on your own, if you don't forget your key idea.
But I've come to see one of your games and honestly, your theoretical knowledge are completely sufficient. You used the 5...g6 variation against the Panov attack, and I don't see why would you need to know more than the 5 first moves, if you don't forget the key ideas.
Hi Chess.com community. I wondering if any advice can be shared on opening theory. Im at 1300 and i realised that if i learn opening theory it will help me alot. Anyway, how should one go about learning the theory - Do you just have to write out every possible variation and memorise it or is more important to understand each variations position. If its just brute force and memorisation then how deep should I learn each variation ?
Thanks