Sicilian defense: Scheveningen variation with a6

At the club level. pretty much anything is playable.  I have been playing a line of the Benko Gambit that is considered busted at the GM level.  It has proven effective against Experts.

5.a6 is the Najdorf. With 6.e6 it can be played like a Scheveningen, which is fine. If u want to play the “Scheveningen” you NEED to play 5.a6 and then hope for Be3 e6 (6 Bg5 e6 is Fine but doesn’t resemble a Scheveningen) because 5...e6 6.g4! gives Black a bad position they will be lucky to hold.

Difficult to say 

About equal I'd say, but it doesn't really matter because 6.g4 is the reason nobody plays the pure Scheveningen these days.

It is false that "nobody plays the pure Scheveningen these days" or that black is "lucky to hold" after 6. g4.   

Ok

1. Very few strong players seriously play the pure Scheveningen these days. Of course, there are a few people who still do, but very very few in comparison to the Kan, Taimanov, Dragon, Najdorf.

2. Yeah, Black would be extremely luck to hold against 6.g4. I'd like to see how you intend to respond and comfortably hold against g4

It seems to me that many times Black wastes a tempo by playing e6 because at some point he looks to play e5, so it would seem to make more sense to play the Najdorf with a6 and then e5 immediately. FizzyBand is right that the Keres Attack with 6.g4 is dangerous.

You can play the Najdorf with e6 (and in some cases, you must play it with e6 because e5 is simply bad against some of White's 6th moves).  As already mentioned, the main reason 5...e6 is not played is due to 6. g4! which leads to an English Attack style game that has been accelerated for White.

Honestly imo I think the Scheveningen is simply an inaccurate move order of the Najdorf. For example, if White (wrongly) meets the Scheveningen with 6. Be3, black can (and often will) go a6 and transpose to the Najdorf with 6.e6. In fact it is rare that in the Scheveningen Black will not eventually play a6 if White plays normally. The only reason the 5...e6 move order is inaccurate is that it undefends the g4 square and allows White to get the attack on quickly and easily with g4. Black should always play the 5. a6 move order and can generally play e6 next. Now Black is fine because if White tries 6.g4 now, Black just takes it with a much better position. Because of this, White is forced to develop a slower attack.

Check a Database. Classic Scheveningen still gets much play at IM and GM level. Fashion comes and goes. Keres attack... much overrated, like the Minority attack. Having said that, I do prefer the early a6 hybrid version. If White plays g5 it stays a Najdorf... if not, transposes to a Scheveningen. According to the CPU here, anyhow.

No you’re wrong on the Keres’. Check out GM Negi’s book. He is arguably the greatest 1.e4 theoretician of our day. As I challenged another member above, show me how Black is fine against the Keres

At the 2350+ level, there were 83 games played in the Scheveningen proper in 2019.  For comparison, there were 1679 Najdorf games played at the same level in the same time period.  For further comparison, the Dragon was played 129 times, the Classical 504 times, 2..e6 variations 1702 times, and 2..g6 variations 149 times.  So yes, the Scheveningen is played far less frequently than the other main lines.  The main reason for that is the Keres Attack.

White scored wins 42.2% (+35), draws 34.9% (=29), and lost 22.9% (-19) from the starting position.

In 42 of those 83 games, White played the Keres Attack, scoring +20=15-7.

Does the Keres refute the Scheveningen?  No, but it certainly makes it much more difficult to play.  Which is why even Kasparov preferred going into it with a Najdorf move order to avoid the Keres Attack.  Black's practical results are much better when going into a Scheveningen setup through a Najdorf move order.

This is utter nonsense. The very basics seem to elude you. 

Black would not "be lucky to survive" at all. Black would have a great game provided he knew the fundamentals of the opening, just like any sharp opening still played at the highest levels - and even many that are not.   

You'd like to see ME do it? Are you joking? This is an elite supergrandmaster opening used by the world's elite to this day. It's not as popular as the Najdorf but it has its place as a lesser known avenue to go into. It suits some players' style better, and has the benefit of mixing things up a little, players get experience and knowledge in it as their specialty, just the same reasons that any lesser played opening are still logical to play.

It's not even as if it's like the King's gambit that is basically refuted at the super gm level, but it's still highly successful at lower levels. The Scheveningen still occupies a clear space in elite games, even if yes it's a lot less often played than the Najdorf. The Pirc is probably quite seldom in super gm games, does that mean it's suddenly a pile of ***** and black is lucky to hold on? You're talking about tiny, tiny theoretical advantages, black isn't "lucky" to hang on at all.  

Foolish post. 

Ok, but you’re completely ignoring my point on the Keres by not giving concrete lines showing the Scheveningen being OK against the Keres. I want to see your lines that prove that Black is fine against the Keres.

It is a bit hyperbolic, but he is not far off from being correct.

The Keres Attack puts Black in a very defensive posture very early on.

"When we published Experts vs the Sicilian in 2004, ..., and GM Viktor Gavrikov chose 6. g4 against the Scheveningen.  Already then, but to a greater extent now, the Scheveningen has become a marginal opening - played so rarely that it has become a subection of the Najdorf in this book" - GM John Shaw, Playing 1. e4:  Sicilian Main Lines

"The Keres Attack has long been regarded as one of the toughest challenges to the Scheveningen...." - GM Parimarjan Negi, 1. e4 vs The Sicilian III

"This is the 'pure' Scheveningen, which is under a cloud because of the Keres Attack" - GMs Jesus de la Villa and Max Illingworth, Dismantling the Sicilian

de la Villa and Illingworth go on to mention that Black's options are limited because if he allows g5, White has a "turbo-charged English Attack".

In short, you have the 3 most respected 1. e4 repertoires against the Sicilian all recommending the Keres Attack, and all concluding a strong edge for White.

It is really only used as a surprise weapon.  Virtually no GMs use the Scheveningen as their main weapon.  See the statistics from my previous post to see why.  Additionally, it is not only played FAR less than the Najdorf, it is the least played mainline in the Sicilian at the IM/GM levels.  Does that mean it is unplayable?  Of course not.  However, the reason it is not anyone's main weapon is due to the Keres Attack.  If everyone knew you were going to play the Scheveningen, they would prepare the Keres Attack against you every single game, and Black's results are very bad in that line.

The King's Gambit is not refuted; rather, it has basically been worked out to a draw.  In other words, if it were your main weapon, Black would simply need to knock out ~35 moves of theory and shake hands.

I could have sworn you had "Caro-Kann" in there before I clicked quote, but just in case:

The Caro-Kann was played 2414 times in 2019 at the IM/GM levels.  White won 33.1%, drew 42.2%, and lost 24.8%.  It is played quite often at that level.  It has not been in fashion at the World Championship level recently, but that is due to fashion, not so much results.

The Pirc was played 650 times in 2019 at the IM/GM levels (with very similar results:  White won 35.3%, drew 37.5%, lost 27.2%).

The Pirc was played more than 6x the amount of the Scheveningen last year.  The Caro-Kann more than 25x.  While I agree that lines can go in and out of fashion, the main reason masters do not play the Scheveningen against other masters very often is to avoid getting into a sharp theoretical battle with the Keres Attack (where White's attack is straight-forward and easy to play while Black's defense rests on the edge of a razor blade!)

While the Pirc and Caro-Kann have "tiny theoretical" edges for White, the Keres Attack is more than just a "tiny" advantage.  If you look at it with engines, you see Lc0 evaluating the position after 6. g4 at +0.75-1.00 (strong edge for White!), and SF 11 evaluates it at anywhere from +0.50-0.70 depending on the depth you let it go to (again, strong edge for White).  Granted, those are engine lines, but if you look deeper into it, you'll see that on every move, White has 2-3 good options and Black only has 1 option - and this goes on for the next 8-10 moves.  This is why players tend to avoid it:  practically, it favors White.

His post was a bit hyperbolic, but not at all foolish.  If you want to play the Scheveningen structure, the better way to do it is to go into it via the Najdorf move order.  Which is what Kasparov did for all but 2 games in his career.

I used to analyse Keres long time ago as white and I could not find proper ways how to dismantle black position. Yes it is not easy to play against g4 setup but there is lots of ways how black may continue, and if white makes single mistakes (loss of tempo, puting pieces on incorrect positions...) black would manage easily.

why is not played more often, think it is just matter of fashion.

As mentioned earlier, it is not simply a matter of fashion.

Or, to show that White has an easier time, a less perfect game.

When White is winning almost half of the games played at the top levels in a line, and drawing over another 1/3rd, it is not just fashion keeping the line from being played.