Lever evaluation

[cdani]

Please do not forget to try unopposed lever on the 4th rank, might be promising.

It was already inside the patch of unopposed levers, so was a little good.

OK, but the size of the bonus for the 4th rank should be very small, maybe 1/4 of that for the 5th rank.

Also, when trying it make sense to try separately, not to mingle with higher ranks. AT least what I see on the board is that such levers have some meaning chesswise...

Thanks again for the feedback.

Yes, I will try different values once I know what works for Andscacs.

[Gerd Isenberg]

Mr. Kmoch did a great job coming up with the lever concept.

Only thing not entirely positive about it is that he mostly suggested concepts that do not quite work, like inner/outer levers, etc.

There are things that work for levers, and things that do not work.
Just like for every other pawn.

If you have 10-20 standard pawn features, of course you can combine those in a way that they produce a whopping one, 2 or 5 thousand or more specific pawn sub-features, but the trick is to be able to combine the different features the right way, for some combinations are fully meaningless, while others should be quite productive.

Specifically for levers, one of the most important features is whether the lever is opposed or unopposed.
People have gotten accustomed to using the opposed/unopposed flag only to assess the extent of weakness of backward and isolated pawns, but of course, the flag could be used on many other occasions.

One aspect with evaluating levers is the interaction with quiescence. Since both sides have the option to mutually capture each opposing lever pawn, the side with the less advanced or otherwise weaker evaluated lever pawn is encouraged to liquidate the lever, while the more advanced lever pawn will avoid the pawn exchange. If the weaker side was/is not able to void the lever, there might be tactical threats. The proposed lever bonus seems an extra bonus for keeping status quo or tactical tension.

[Lyudmil Tsvetkov]

Mr. Kmoch did a great job coming up with the lever concept.

Only thing not entirely positive about it is that he mostly suggested concepts that do not quite work, like inner/outer levers, etc.

There are things that work for levers, and things that do not work.
Just like for every other pawn.

If you have 10-20 standard pawn features, of course you can combine those in a way that they produce a whopping one, 2 or 5 thousand or more specific pawn sub-features, but the trick is to be able to combine the different features the right way, for some combinations are fully meaningless, while others should be quite productive.

Specifically for levers, one of the most important features is whether the lever is opposed or unopposed.
People have gotten accustomed to using the opposed/unopposed flag only to assess the extent of weakness of backward and isolated pawns, but of course, the flag could be used on many other occasions.

One aspect with evaluating levers is the interaction with quiescence. Since both sides have the option to mutually capture each opposing lever pawn, the side with the less advanced or otherwise weaker evaluated lever pawn is encouraged to liquidate the lever, while the more advanced lever pawn will avoid the pawn exchange. If the weaker side was/is not able to void the lever, there might be tactical threats. The proposed lever bonus seems an extra bonus for keeping status quo or tactical tension.

Advance levers do all kinds of stuff: open files, attack the king shelter, create tactical threats and increase the tension, as you rightly point out, etc.

Some unopposed levers are additionally future candidate passers or transit the stage from candidate passers to passers, etc.

As they are quite frequent, they are also very much subject to inconsistencies of behaviour, so much so that a fair portion of advanced levers are actually a liability. But the benefit still seems to outweigh.

Currently I am much more interested in long chains, unfortunately no one or almost no one is able to derive some benefit from that, while in actual case there is very much to gain from that.

I am even inclined to think that long chains are one of the most important eval features altogether.

[cdani]

Now I'm trying joined double lever. I will post.

Was a tiny maybe 2 elo win at 15000 + 15000 games.

[Lyudmil Tsvetkov]

Now I'm trying joined double lever. I will post.

Was a tiny maybe 2 elo win at 15000 + 15000 games.

Thanks for the feedback, Daniel.

Tiny 2 elo here and tiny 2 elo there...

I am especially interested at what happens with unopposed lever on the 4th rank with bonus equal to 1/4 the size of the bonus for lever on the 5th rank.