Search extensions

[Uri]

What are search extensions? Is it related to quiescent search?

[Dann Corbit]

What are search extensions?

Search extensions are where you search interesting moves deeper than the normal current ply depth. Suppose that you see enormous danger for the opponents king. Maybe we should look a little deeper.

Is it related to quiescent search?

Search extensions are not related to quiescent search. Quiescent search is where you do a SEE exchange of captures until there are no more winning captures. That way {for instance} you do not capture a pawn with a queen, only to have the opponent retake your queen with a pawn.

[wgarvin]

What are search extensions? Is it related to quiescent search?

Here's some info about search extensions, including a list of situations where it might make sense to extend the search:
http://www.frayn.net/beowulf/theory.html#extend

[Uri]

Suppose that you see enormous danger for the opponents king. Maybe we should look a little deeper.

What qualifies as enormous danger for the opponents king? I guess weak pawns, open files or diagonals which point directly toward the opponents king, pawn on f6 (or h6) combined with a queen on h6 (or on f6) is also very dangerous for the opponents king.

I am not so good at chess so i don't know all the cases which quality as enormously dangerous for the king.

[Dann Corbit]

Suppose that you see enormous danger for the opponents king. Maybe we should look a little deeper.

What qualifies as enormous danger for the opponents king? I guess weak pawns, open files or diagonals which point directly toward the opponents king, pawn on f6 (or h6) combined with a queen on h6 (or on f6) is also very dangerous for the opponents king.

I am not so good at chess so i don't know all the cases which quality as enormously dangerous for the king.

It's a complicated question. You will find that some programs spend enormous energy calculating it.

http://chess.about.com/library/weekly/aa03e17.htm
http://www.jeremysilman.com/chess_instr ... begin.html
http://www.associatedcontent.com/articl ... _king.html
http://query.nytimes.com/gst/fullpage.h ... A960948260

Here's Colin Frayn's King Safety summary:
King Safety :
1. Encourage the king to stay to the corner in the middlegame.
2. Try to retain an effective pawn shield.
3. Try to stop enemy pieces from getting near to the king.

[gladius]

King safety is a really fun topic. Some combination of enemy pieces attacking squares near your king, and the number/proximity of the pieces is usually one part of the calculation. Pawn storms/shields (keeping your pawns in front of the king close, and lauching pawns against the enemy king) are also a huge factor that was causing my program to get ripped to shreds by other programs that had that term.