## Pawn Storm - Theory

Discussion of chess software programming and technical issues.

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carldaman
Posts: 1618
Joined: Sat Jun 02, 2012 12:13 am

### Re: Pawn Storm - Theory

carldaman wrote:
D Sceviour wrote:
carldaman wrote: [D]4rrk1/pp1n1pp1/2pb1q1p/3p1b2/1P1P4/PQN1PN2/4BPPP/2R2RK1 b - - 0 14
The game I posted in the above thread is a good example of that. The black king is never in danger even after a big chunk of his shelter has stormed forward.
Hello Carl,
My own engine Schooner finds g5 in only 6 ply, yet Stockfish9 says b5! is the best move. SF9 says g5 gives nothing more than equality. One cannot argue with the machine, but we can try to duplicate some of the reasoning in code.

In your given position above, black is never in danger because white has no current attack, and no white attack on the king on the horizon. Thus, the black pawn structure does not make a difference. This is described in item:

(3) Challenge kings with some other piece beside the pawns. The pawns themselves cannot threaten the king.

Some programs consider other measures in describing the attacking situation. One is king tropism - or how close the pieces are to the king. Here, blacks tropism is higher than whites, and this is important (unless you are using Stockfish9 to analyze).
White has no current attack in large part because of the pawn chain structure (b7-c6-d5/f2-e3-d4), which (diagonally) splits the board in two halves, with many of the White pieces in the wrong half, but all the Black pieces in the 'attacking' half.

The pawns alone cannot attack the king, but they can a) threaten to dislodge defensive pieces (Nf3), and b) open up lines of attack by creating levers (pawn breaks, h5-h5, hxg3).
I just wanted to add that it's VERY impressive that Schooner plays 14...g5 in the above position. I even checked it for myself in Arena, to see with my own eyes. As you mentioned, Stockfish wants to play b5, thinking unnecessary defense first, rather than 'obvious' attack. Neither Komodo 11 nor Houdini 6 would play the attacking g5 either, opting for the same solid but lame b5.

This is a huge problem with today's top engines. They seem to prefer stodgy solidity and safety over everything else. There is too little creativity and risk-taking shown, while the potential already provably exists for it, if only it were attempted. It's as if all that enormous strength top engines have is wasted on anti-chess, playing not to lose, rather than to win.

(Of course, I'm generalizing here, as anyone could certainly provide a counterexample where SF, K or H managed to produce a sparkling display of attacking chess. But on the whole, what I'm saying is mostly accurate.)

I lost a couple of sparring games against Schooner since my last post. Very nice down-to-earth style, almost as if facing a real human master! It is no fluke that it chose g5 in the test position. Dennis, if you put style first and make Elo secondary, you'll have yourself a dandy of a chess program. You're already well on your way.

D Sceviour
Posts: 393
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### Re: Pawn Storm - Theory

carldaman wrote:I lost a couple of sparring games against Schooner since my last post. Very nice down-to-earth style, almost as if facing a real human master! It is no fluke that it chose g5 in the test position. Dennis, if you put style first and make Elo secondary, you'll have yourself a dandy of a chess program. You're already well on your way.
Thank you for playing Schooner. I wondered if anybody had tried it yet. It does have a very aggressive style with successful crash-bang sacrifices. However, for some people elo is everything and style is nothing.

carldaman
Posts: 1618
Joined: Sat Jun 02, 2012 12:13 am

### Re: Pawn Storm - Theory

D Sceviour wrote:
carldaman wrote:I lost a couple of sparring games against Schooner since my last post. Very nice down-to-earth style, almost as if facing a real human master! It is no fluke that it chose g5 in the test position. Dennis, if you put style first and make Elo secondary, you'll have yourself a dandy of a chess program. You're already well on your way.
Thank you for playing Schooner. I wondered if anybody had tried it yet. It does have a very aggressive style with successful crash-bang sacrifices. However, for some people elo is everything and style is nothing.
And I had no idea till today, after this thread caught my eye, basically by chance. Most engines in that rating range are unknown to most, and even if aware of, there's no way to know about the actual style until trying first hand or hearing it from someone else.

[I hope Brendan is reading this thread. He makes it his business to popularize such exciting engines - Schooner deserves better fame! ]