How are the Chess piece values determined?

I need to know the mathematics or algorithm by which the values of all chess piece (like king = 鈭? queen = 9, rook = 5 etc.) is found.|||I play chess seriously and frequently in competitions (although not brilliantly), so I have some understanding of what's behind this.





I think experts compared how likely a win is with certain combinations of pieces. So if one person had lost their queen (9 points) but gained rook + bishop + pawn (5 + 3 + 1 = 9 points) it is observed that they still have about equal chances in many games.





In the same way a person ending with king (of course) + bishop + 2 pawns has about an equal chance as a person with king and rook. If you give up both knights to gain a rook and pawn then this is roughly a fair exchange.





If one person ends with a bishop and his opponent has three pawns then generally neither can win. The bishop can be given up to stop the pawns "queening" and none get through. However, in general, a bishop can't stop four pawns. This is why a bishop is reckoned to be worth about three pawns.





Of course these values are not perfect - it depends on the exact position. However, they are a good guide to those learning the game, as to which exchanges are likely to be beneficial or not.





They are certainly NOT arbitrary values, but there is no real mathematics behind it, just experience in chess playing.|||It is completely arbitrary. Some people just sat down and decided that this peice gets this value, and so one.





No algorithms.|||Are you sure there is an algorithm? Check on Google, Yahoo, or Your Favorite Search Engine.





But honestly, I think it is determined by each piece's power.





Pawn can only attack 2 squares max.





Rook can attack 14 squares max.





Knight can attack 8 squares max.





Bishop can only attack 14 squares max.





King is an obvious exception. It can only attack 8 but the King is THE GAME.





Queen is 28 squares max.





So..... Think this over.