Hotspots

[Lyudmil Tsvetkov]

Maybe a bit of discussion with specific examples about hotspots/king binds.

[d]3r1nk1/pp1q1p2/2p1r1p1/3pP1Pp/3P3P/P1N1P2Q/1P6/2R2RK1 w - - 0 28

Above, white is winning, but SF does not recognise this still, and I think it is even very far from knowing white leads by more than a full pawn here.

What is evident, is that the center might be considered as closed here, as d files is closed, and things are static on the e file. Also, there is a backward f7 pawn.

So I really think two necessary conditions for a patch along these lines to succeed is to require a closed center and a backward f7 pawn/c7 pawn with a queenside c6 bind.
Also, it might make sense to further restrict king location to h8,g8,h7,g7, as on f8, e7,e8 the king can sometimes already slip away to the queen side.

I hope Vince will not be angry for me posting this, the topic just seems interesting, as I do not think many programmers have paid attention to it in the past.

Anybody posting similar bind positions to elaborate on is very welcome.

Maybe even Vince can post one or two such examples from his database.

[Lyudmil Tsvetkov]

OK, I wanted to post this in the old thread with eval ideas, but I went wrong.

Never mind, the old thread is already too long, maybe I will just post here couple more ideas.

[Lyudmil Tsvetkov]

I posted in the past a suggestion to give bonus for a rook on a square adjacent to our king.

Just a little specification: not all adjacent squares are good, but just a few of them on the rank immediately in front of the king, and when the king is on either g1 or h1 on the first rank.

So, in actual case, I would give the small bonus for rook piece shelter, some 5-8cps, to any rook on f2,g2,h2 with Kg1, or g2,h2 with Kh1.

This is good for 2 reasons:

- the king is covered by the rook in case there are no pawns or minor pieces to do that, and
- very wisely, with a black king also castled short, such a rook attacks on an x-ray the squares of the enemy king shelter, which is very important indeed, and frequently might decide games

Of course, the bonus will be due just for the mg.

This is also part of king safety, but has at the same time attacking implications.

[Lyudmil Tsvetkov]

Of course, there is one single backward pawn of all available on the board that is most troublesome and deserves the biggest penalty.

Obviously, this is the f7 backward pawn of the black king shelter.

Backward pawns deserve a penalty, but it is not equal for all backward pawns.
Backward pawns part of the king shelter deserve a bigger penalty, but again, it is not equal for all such backward pawns. Pawns on the g and h files might be less of a liability.

But f2/f7 backward pawn always deserves a huge penalty above the already assigned penalty for a backward pawn.

[d]6k1/5p2/8/4P3/8/8/8/6K1 w - - 0 1
above, black f7 is backward, part of the king shelter. It does not matter at that if there is a black pawn on e6 or g7/g6, f7 is always backward whenever there is a white e5 pawn.

Please note, that a white g5 pawn instead would not quite be so efficient backward-maker, as in this case its attack span will point away from the shelter, which is not the case with an e5 white pawn, whose attack span points towards the shelter.

So, I would simply give some 15cps additional bonus to any e5 white pawn with a black pawn on f7, or, if you want, a 15cps penalty for any black pawn on f7 with a white pawn on e5.

The bonus/penalty will be due just for the middlegame.

I do not think it is necessary to specify the king locations in this case, as in 95% of cases kings will castle kingside, but apart from that the usual piece placements will indicate that such a constellation is more forcing than a black c7 backward pawn with a white backward-maker on d5 and black king castled long.

So I would just give the bonus for any white pawn on e5 with a black pawn on f7.
In this case, asymmetry is fully justified.

You think this is naive; well, just try it.

[Lyudmil Tsvetkov]

Well, 2 things such a bonus will see is:

- necessity for black to play f7-f5 early to get rid of the f7 backward pawn, and
- necessity for black to play early f7-f6 with an exchange of the f6 for the white e5 pawn, alleviating the pressure

I think hotspots are much more dependent on the presence of a backward f7 pawn rather than the presence of a closed center.

You might in a range of cases do without a closed center, but you almost never can do without the condition of an existing f7 backward pawn.

[d]rnbqk1nr/ppp2ppp/4p3/3p4/1b1PP3/2N5/PPP2PPP/R1BQKBNR w KQkq - 0 1

I have the vague feeling, actually a certainty, that a similar bonus might help SF play e4-e5 above in the French Winawer line, as well as in a wide range of other openings, rather than exchanging on d5.

Of course, playing e4-e5 above makes the f7 black pawn backward, which will not be the case if ed5 is played.

An engine being able to recognise e5 is the best move above is a minimal requirement for a fairly decent closed positions play.

[Lyudmil Tsvetkov]

Sorry, SF guys, I just can not resist seeing Joerg pushing a piece values patch on the framework, and me not being able to do so...

I had the opportunity to suggest in the past a change for a single piece value, the pawn, but never for all pieces at the same time.

It is simply irresistible, I am sure my values are going to pass after 500 games.

Below are my suggested values:


PawnValueMg = 194, PawnValueEg = 256,
KnightValueMg = 817, KnightValueEg = 846,
BishopValueMg = 840, BishopValueEg = 865,
RookValueMg = 1278, RookValueEg = 1294,
QueenValueMg = 2514, QueenValueEg = 2547,

MidgameLimit = 15581, EndgameLimit = 3998


Lyudmil, you possibly told you could push one other patch in the future, could I ask you for the last time that we try this one, just for a single time, maybe when there are fewer tests going?
I would be very grateful, it is simply irresistible.

Or maybe someone else could help me with pushing the above patch, I am sure Joerg will not mind to have one other version tested.

[Lyudmil Tsvetkov]

People might think that this is a stupid, asymmetric, inapplicable term, but this is not so.

Actually, it is quite a frequent term, and the really good thing about it is that it appears early into the opening, with ample opportunity to shape the further development of the game.

If I had an engine myself, I would not hesitate to introduce this or similarly relevant term at the earliest opportunity.

[Lyudmil Tsvetkov]

And of course, I forgot to mention, this involves a central pawn and a pawn of the king shelter at the same time, speaking volumes about its importance.

[vincenegri]

I hope Vince will not be angry for me posting this, the topic just seems interesting, as I do not think many programmers have paid attention to it in the past.

No, but you will have to buy me a faster computer

[Lyudmil Tsvetkov]

I hope Vince will not be angry for me posting this, the topic just seems interesting, as I do not think many programmers have paid attention to it in the past.

No, but you will have to buy me a faster computer

I will, I will, as soon as the hotspots patch passes.