Slav or semi-slav !? To secure a win against higher rated opponents !?

I'm talking about OTB chess and only blitz format here.

So my question is simple, when facing higher rated opponents, say from CM to strong FM range.

Is it better to play slow and sturdy, positional grinding  (with some tactics of course) 

OR 

Wild tactical  (and some positional of course as well) battles , with semi-slav opening.

Also very important, you don't know your opponents, what they usually play or how to prepare for them.

There is no cookie cutter answer to that.  When you do not know the specifics of your opponent, play what you know - plain and simple!  If I know nothing about your style of play and I am about to face you, and I have Black, rest assured you will face a French or Kings Indian!

#2

First of all french defence is for e4 opening and we are talking about d4 here 

Second of all you are not playing neither one or know about (in depth) it, so why are you here? (smile).

And third of all , facing you , as much as you want it , you wouldn't have a chance to play neither french or kings indian against me lol You will have to adopt to my sharp,fast and fearless weapon Sokolsky, so pack your french and kings indian far far away lol

The reason I'm asking is , because I want to go all in, in theory in just one of them , to be well prepared  (much better then my opponents) and crush them with it. 

I'm planning on getting a book (and not just limited to ) to study,  but I need to know which opening to pick !?

Book I'm planning on is :

Grandmaster repertoire Classical Slav 

OR 

Grandmaster repertoire Semi-slav 

edited moderator AndrewSmith 

The former book is a little bit more comprehensive in that it covers the Slav sidelines (e.g. d4 d5 c4 c6 Nf3/Nc3 Nf6 e3, the exchange Slav), which are not covered by the Semi-Slav book.

It doesn't matter if you are planning on entering the Semi-Slav by the Queen's Gambit move order, but then there are other lines that you'll have to learn to play against (the Catalan in particular has become very popular recently).

As for the original question, it's a matter of taste and your feeling for the positions. Both are possible to play for a win and fairly theoretical.

And you will almost never "crush your opponents" in a Slav/Semi-Slav unless they walk into a main line (the Botvinnik for example) without knowing what they are doing. You should probably play the KID if you want to (have time to) memorize tons of theory and wipe your opponent off the board.

I'm curious as to why ThrillerFan defers from the Alekhine, Grunfeld, etc. As far as the question, longterm Semi-Slav, if you are an intense, accurate, and like theory

learning one opening to perfect extent will not make you much better in you efforts, why?

first, each opening takes two, your oponents may, and will, deviate from what you prepare for sure, even with less sound lines once they put you out of preps you are doomed

and second, no player was crushing others with theory only, kasparov? yes, but because he was skilled attacker

if you want to crush oponents you should increase your overall skills on board

My limited experience against playing masters, FMs and IMs, you want a position that is a bit messy (or you having a mobile pawn center with active piece play), but without having to play through an opening that has been worked out well into the middle game. The quieter a game is, the more likely you will easily lose against a stronger player. Hard to tell OTB the difference between 'casual' FMs and IMs, but it's quite noticeable the difference between a 2200 player and a FM.

THANK you everyone for your input, I'm definitely taking notes and some interesting ideas here.

Nice informative answer! From a high rated player too.

Just one nuance, no matter what opening is it better go sharp and wild against higher rated opponents or slow and sturdy, positional?

It's always best to throw Wild Punches at better opponents. 

There are 5 main types of pawn center (see month 2 of chessmasterschool.com core course).

Closed

Mobile

Static

Open

Dynamic

I admit my weaknesses, unlike many.  One of mine is the ability to grasp the concept of the mobile pawn center, which the primary openings that lead to the defined position are the Alekhine and Grunfeld.  When Black, I get rolled over by White's mobile pawn center.  When White, that same center is an over-extended weakness.

That is why I avoid the Alekhine and Grunfeld like the plague.  The Dragon and Modern Benoni is just that I do not have time to keep up with every defense that requires 30 book moves to stay in the game.  Of those that do, I decided to put my time towards the Najdorf and Kings Indian.

Agreed!  But this should be done with White though, not Black.

Diversify your game when you have the advantage.  Play what you know left and right when behind the 8 ball.  With Black, diversify within the system, but do not jump around.  For example, if you play the Kings Indian, play the 7...Nc6, 7...Nbd7, and 7...Na6 lines, but do not try to jump ship and play the Slav then.  If you are a Semi-Slav player, maybe play the Moscow and Botvinnik, or the 8...a6 Meran and 8...Bb7 Meran, but do not then jump ship and try to mix it with the Modern Benoni.  Also, you say once they deviate you are doomed.  If you memorize, that is true.  If you study an opening properly and understand it, you do not have that problem.

In slow, over the board competition, people do not beat my French by trying to throw me off because I understand it, not memorize it.  In the few times I lose in the French, it is against the Advance, Tarrasch, 3.Nc3, etc, not odd garbage like 2.f4.  I even wrote an article on the Charlotte Chess Center blog on beating the garbage lines (The French Connection - Volume 9).

The Grunfeld, sure I can regurgitate 1.d4 Nf6 2.c4 g6 3.Nc3 d5 4.cxd5 Nxd5 5.e4 Nxc3 6.bxc3 Bg7 7.Bc4 c5 8.Ne2 Nc6 9.Be3 etc, but that does not mean I understand it and I don't!  For example, play 5.Bd2 and I am probably dead.  Do something odd against the French against me and you will be the one fighting to survive.  That's the difference between parroting an opening and actually knowing it!

It takes 2 medium sized blunders, in theory, to lose with White.  It only takes 1 with Black often times to lose.  Would highly advise that you learn one opening against e4 and one against d4.  That is one full opening each, not one variation.  If it is say, the Nimzo-Indian/Queen's Indian, then against 4.e3, you should at least understand 4...d5, 4...c5, 4...b6, 4...O-O, and 4...Nc6, and actually play at least 3 of them, just as an example.

Again, do your broader diversification with White.

Just embrace yourself.

With no knowledge about the opponent, it is better to play the kind of position you are good at and comfortable in.

You didn't really answer my question.

What if you are comfortable in both or want to learn one of each, then question still stands.