Yes, not to mention the f4 pawn being also supported by the g3 pawn in fianchetto openings such as the KID/KIA, which usually rules out exf captures and allows the pawn chain to be extended (in theory), in most cases followed by g3-g4, h2-h4, g4-g5-(g6) pawn storms.Lyudmil Tsvetkov wrote:Precisely, one of the assets of such c and f file levers is to possibly extend, under certain conditions, a longer chain, either on the king, or queen side.carldaman wrote:I usually read your posts, Lyudmil, as long as I have the time, and reply if something needs to be said, but not always, since time may be too limited. A lot of times, a non-response may actually signify tacit approvalLyudmil Tsvetkov wrote:I see that no one is interested in my stupid posts, but I will take the freedom to post one last very brief message, as I find the topics worth it.
One simple rule for pawn checks:
- pawn checks are much less important than the threat of the check itself, in sharp distinction to all kinds of piece checks, where the check itself is more important than the threat of a check
- unsafe pawn checks are far more important than safe pawn checks, so a check not supported by any own pawn or piece is usually more valuable than a check supported by own pawns and pieces
So that, with pawn checks, everything works the other way.
The main reason for this paradoxical behaviour is that pawn checks are mainly a tactical weapon.
[d]6k1/7P/2k5/8/1PK5/5p2/8/1B4K1 b - - 0 1
The white check with the h7 pawn, although defended by an own bishop, is much less important than the threat of a check/potential check by the black pawn on f3 upon the white king, with f3-f2, although that check would be unsafe and unsupported.
As said, pawn checks are mainly a tactical weapon.
In the endgame, potential pawn checks like b4-b5, with the checking pawn supported only by the own king, are also important.
I would give potential pawn checks some 5-10cps bonus, both for the mg and eg, though the mg bonus might be a bit higher.
Passing over to the topic of center levers.
Some engines implement bonus for advanced levers, i.e. bonus for levers on the 5th and 6th ranks. This makes sense.
However, it is also possible to break the symmetry and use the concept also for levers on the 4th rank, that would be symmetrical in terms of ranks, but not symmetrical in terms of files.
Of course, you will try to give the bonus for an outer, less central pawn, attacking an inner, more central pawn. This is one of the suggestions of Mr. Kmoch.
Unfortunately, it will not work in most cases.
It works only in the center, and apart from that, there are only 2 squares on the entire board that deserve the bonus: a c4 white pawn attacking a d5 black pawn, and an f4 white pawn, attacking an e5 black pawn. Other tries might not work, but those 2 squares are very important.
Reasons for giving bonus for those particular squares?
- a c4 white pawn attacking a d5 black pawn might be traded for a more valuable, more central e6 black pawn, but also for less valuable c6 black pawn, that is on the same file, but less advanced, so that is not the valid reason
- a good reason is that it is always well to attack the center, the earlier the better
- another good reason is that the concept helps flank attacks like c2-c4 and f2-f4, which are very efficient, especially f2-f4, and particularly when made earlier
[d]6k1/8/8/3pp3/2P2P2/8/8/6K1 w - - 0 1
c4 and f4 pawns/center levers get the bonus here, in spite of the fact that the attacked enemy pawns are also on the 4th rank
I would give some 5-10-15cps, who knows, to center c4-d5 and f4-e5 levers, just for the middlegame.
OK, sorry for posting, I know no one is interested, but at least I am sure Carl will read it.
I've always been a fan of central levers, even flank levers. In particular, I like the f4-e5 lever even more if
a) White has a pawn on e4 as well,
b) the f5 square is empty and thus f4-f5 is a viable option to extend the pawn chain, and
c) Black has already castled Kingside.
I think a hefty bonus of 30cps (or more) is in order if all 3 conditions apply to the f4-e5 lever. Gaining space with f4-f5 should be encouraged by further bonuses if the King is on that side, while a c4-c5 advance on the Queenside should be penalized if extending the chain in the wrong direction, away from the King.
Brief Regards,
CL
Another positive side is that f4 or c4 pawns are supported by the respective bishops on c1/f1, so white might wait with the tension created by the lever, until the opponent captures and those bishops are swiftly developed. So the center lever of this kind is more burdensome to the opponent. For example, with an f4-e5 lever, e5 is not supported by a bishop, usually by an already developed knight, besides being more central pawn and less advantageous to trade.
I am also a fan of applying flank lever concept to other possible levers, for example b4-c5, supposedly bonussing the less central b4 pawn in this case. However, try to do do this and give such a bonus. I think it will not work in the general case, as it is not clear who benefits from the tension created by the lever. Sometimes the b4 pawn, and sometimes the c5 pawn.
Although the b4 pawn is less central than the c5 pawn, and thus advantageous to trade, it is not supported by either a bishop or well placed knight in the usual case, and also can not possibly extend any useful chain with b5, so this flank lever is entirely conditional upon specific circumstances on the board, that might arise or not arise. Thus, you do not know which side usually benefits.
Practical play also shows that flank b4-c5, b5-c4, g4-f5 or g5-f4 lever thrusts appear mainly in the form of b7-b5 thrusts in specific and limited in number lines of the Benko/Volga and Bluemenfeld Gambits, the Modern Benoni and very rarely in a few lines of the black KID.
With c4-d5/f4-e5 center levers you might claim with a fair amount of certainty that they are advantageous. But who knows what works in an engine and what not?
I think b4/b5 as a break (or even a gambit) usually has a good reputation in the Volga/Benko/Blumenfeld/Benoni set-ups, and can also be a good try in certain Wing gambits vs the French or Sicilian. However, those ideas involve mainly Queenside play. Kingside flank attacks can be a lot more insidious and engines struggle more in this area.
CL