Poll: What is the most minimalistic opening repertoire?

Yeah, I've heard from many people the london/torre system is near the top for requiring least theory; but also heard masters speak badly about the torre (maybe for being super trash, or really boring).

Seems like good video here covering london vs torre
youtu.be/RMLuxoOyqQg?t=10

As White, d3, c3, Qa4, and g4, if they can be played safely. As Black d6, c6, Qa5, and g5.
Just pawn storm the kingside and hope for the best.

This thread became way too advanced and difficult to understand. All the comments by the 2000+ rated players without links to the actual games or demonstration boards. I hope someone like @achja or @morningcoffee will come for rescue.

Did anyone mentioned me? :)
Ok so I don't really know how I can help

@Tangelo777 #7 Owen's Defence is 1.e4 b6
The London system can be played against almost anything so I won't tell you the moves just white's basic setup :
en.lichess.org/analysis/standard/rnbqkbnr/pppppppp/8/8/3P1B2/4PN1P/PPP2PP1/RN1QKB1R_w_KQkq_-

Now, #8
1.d4 c5 is playable but after 2.d5 white gets a strong point in the centre for free. You can argue that the same happens in benoni but it's not exactly the same (there white has already played c4 so with c5 you begin a large-scale fight for the dark squares)

#12 en.lichess.org/analysis/standard/rnbqkbnr/pppppppp/8/8/Q5P1/2PP4/PP2PP1P/RNB1KBNR_w_KQkq_-

I honestly don't know if this suggestion was intended as a joke or not but let's say that if it was a joke then it was successful with me

#1 OP
the opening repertoire with the least amount of theory (which is probably what you mean with the word minimalistic) is not to play any opening at all. And this is achieved by playing systems and learning general schemes that apply to them

for example look at this pawn structure from the london system
en.lichess.org/analysis/standard/rnbqkbnr/pppppppp/8/8/3P1B2/2P1PN2/PP1N1PPP/R2QKB1R_w_KQkq_-
and now look the piece configuration and pawn strucure of the black pieces in the Slav defence
en.lichess.org/analysis/standard/rn1qkb1r/pp3ppp/2p1pn2/3p4/2PP2b1/2N1PN2/PP3PPP/R1BQKB1R_w_KQkq_-
It's basically the same, only this time with black
And now take a look at black's configuration in a caro-can or a scandinavian defence en.lichess.org/analysis/standard/r3k2r/ppqnbppp/2p1pn2/5b2/8/8/PPPP1PPP/RNBQKBNR_w_KQkq_-
Again its the same only this time the d5 pawn has been exchanged for the e4 pawn
So basically you only need to know one position, one pawn structure, almost zero opening theory and you can play it anywhere and anytime against all openings whether you have black or white.

Just so you know, this of course a remarkable thing but there is always something ugly in something so wonderful
Imagine it like this, a guy who wants to train his body and only doing pushups. From the moment he wakes up he only does push ups. Now if there was a push up contest anywhere this guy would be very good but if anything else unexpected happened to him and had to walk a bit for example ,he would find that walking is harder than doing push ups when for most other people, it wouldn't be.

@morningcoffee Thanks a lot! I frequently play the London System setup except that the LSB is on d2 instead for f4 in order to avoid it being attacked by a knight and ruin my pawn formation.
Regarding the Owen defence, I don't like it because it gives up the center, wastes time on unnecessary pawn move and creates a bad bishop. Regarding the white's structure in Slav, I like it a lot. It is safe and flexible. There are no backward pawns and targets for opponent to attack.
Your Benoni diagram is not good for white because the queen is out and is a nice target, there is no control of center by white, lots of tempos wasted by pawn moves... I don't like it.
The Caro Kann setup looks good for black. No bad bishops, everything is developed, queen is safe from attacks.
Regarding your last comment, it very important to understand pawn formations since they are called "GPS of chess". The pawns dictate what tactics and weaknesses are available. The players who have your level of knowledge of strategy would beat everyone here every time by creating superior positions and blunder much less.
Thank you again for clearing everything up! You are a life saver!

Just to add a few more things towards the OP.
If you want an easy on openings, you can for example play KIA, King's Indian Attack, setup.
This can be played by white and black.
It is basically the structure d2d3, e2e4, g2g3, Bg2, Nf3, Nbd2.

Game collection : Bobby Fischer Wins With The King's Indian Attack
www.chessgames.com/perl/chesscollection?cid=1017725

You can play this against Caro-Kann and French :
1.e4 c6 2.d3 and 1.e4 e6 2.d3

Another setup is the Lion, which can also be played by white and black. That can even be played after 1.e4 e5 2.Nf3 Qe7?!
Black plays d6, Nbd7, Pf6, Be7, and then starts h7h6, g7g5, Nd7-f8-g6 or e6 and Rg8.

In the Lion opening part you need to take care about the weak point f7.

London system and Torre attack are both fine.
London system has been played a lot by GM Kamsky, but also Carlsen, Giri, Karjakin and other top GMs have played it.
Torre attack as well as Trompovsky are both uncommon for top GMs, but fine for amateur players.
GM Timur Gareev likes to play the Tromp, and so did GM Julian Hodgson and GM Jeroen Piket in the past.
For the Tromp you need to study a bit, because some lines can be very sharp. For London and Torre there is not much to study at all, you just need to know a few ideas. Main idea is to put a knight on e5, except in setups where black plays a quick d7d6.

Apart from all this, an opening move like 1.e2e3 is also quite interesting for amateur players as white. It is a flexible move.
Depending on how black responds white can follow up with d2d4, or c2c4, or b2b3! (Owen's defense might be slightly unsound for black, but playing Owen's defense as white is fine! See games by GM Larsen, Jobava, Nakamura)
At the last olympiad it was even played by GM Carlsen, who won a fine game with it.

HTH

Thanks to all for the enlightening advice given so far. Tonight i'll try to answer a bit more detailed. Best regards, Karl

The most minimalistic opening repertoire is the "empty repertoire" where you are out of theory on move 1.

The most minimalistic repertoire that deserves the name "repertoire" is probably the modern defence for black (g6, Bg7 and d6) and the "reversed modern" / KIA for white (Nf3, g3, Bg2, 0-0, d3, Nbd2).

Other rather simple opening systems for white are the Trompowsky and Pseudo-Trompowsky (1. d4 and 2. Bg5 unless it hangs something) or the London-System (d4, Bf4, e3, often h3 at some point).

For black, a more sound alternative to the modern defence might be playing the French (1. e4 e6) against 1. e4 and the English Defence (1. d4 e6 2. c4 b6) against 1. d4-like openings. (I've actually tried this for fun in blitz and it worked reasonably well.)

Playing these "simple" repertoires / opening systems however can get you into the habit of ignoring what your opponent does and just caring about your own moves.

Therefore, I will instead recommend you to play more "mainline openings" like the Italian Game (1. e4 e5 2. Nf3 Nc6 3. Bc4) or the Ruy Lopez (1. e4 e5 2. Nf3 Nc6 3. Bb5). These openings are imo great for beginners as they're a good environment for improving your chess by "trial and error". - If you make a mistake in a typical 1. e4 e5 opening, you're usually able to understand what the mistake was and learn from it.

Kings Indian Attack I will second for easy play. Basically you can do this against anything black does. But as black you need some kind of opening setup. Maybe go for simplton stuff like me. e4 e5 and d4 d5. If you like the fianchetto setup maybe the Kings Indian Defense is something you can do instead of d4 d5. For e4 though it is not that simple.