Enter Your Reply The Comment You're Replying To Derek Nalls wrote on Sat, Jul 28, 2007 05:41 PM UTC:It is useful to classify inaccuracies and try to define how much inaccuracy is too much with relative piece values. The first, most dangerous inaccuracy is what I classify as a 'direct inversion'. A direct inversion is where two pieces with significantly different values have their order of value reversed from its true existence. I am referring to more than a trivial case of, for example, mistakenly defining the knight (30.00- DN model) as more valuable than the bishop (32.42- DN model) upon an 8 x 8 board IF the reverse is actually true since the values of these two pieces are truly very close. Instead, I am referring to a non-trivial case of, for example, defining the rook (59.43- DN model) to be more valuable than the archbishop (70.61- DN model) upon a 10 x 8 board where the reverse is actually true. Under such a mistaken belief, a player willfully enters disadvantageous, simple 1-to-1 piece exchanges involving his/her archbishop for the opponent's rook. If any game is won where this exchange has occurred, it is against the odds. Incidentally, such simple exchanges are realistically likely to occur in typical games. I think most of us would agree this is too much inaccuracy. The second, potentially-dangerous inaccuracy is what I classify as an 'indirect inversion'. An indirect inversion is where, despite the hierarchy of values for the lineup of pieces being correct, the numerical erraticities within it are great enough to cause incorrect conclusions in evaluating complex exchanges involving more than one piece per player. Derek Nalls relevant FRC pieces upon the 8 x 8 board material values knight- 3.000 bishop- 3.242 rook- 5.088 queen- 9.371 _____________ Reinhard Scharnagl relevant FRC pieces upon the 8 x 8 board material values knight- 3.0000 bishop- 3.4488 rook- 5.3030 queen- 9.0001 ______________ Note that under the RS model, 1 queen + 1 knight (2 pieces) is valued at a total of 12.0001 and 2 bishops + 1 rook (3 pieces) is valued at a total of 12.2006. It values the 3 pieces 0.2005 higher than the 2 pieces- a marginal amount. In practice, it would probably be indifferent to this exchange. Note that under the DN model, 1 queen + 1 knight (2 pieces) is valued at a total of 12.371 and 2 bishops + 1 rook (3 pieces) is valued at a total of 11.572. It values the 2 pieces 0.799 higher than the 3 pieces- a significant amount. In practice, it would probably aggressively pursue this exchange. Due to their contrasting evaluations of this complex 2-to-3 pieces exchange, both players (RS & DN) would willfully enter opposite sides of this exchange as being advantageous. Unless both models are inaccurate so that, in fact, this exchange is absolutely neutral to the interests of both players, one player who willfully enters this exchange will get harmed by it and probably, eventually lose the game. Predictably, it is my contention that a player who trades 1 queen + 1 knight for 2 bishops + 1 rook will probably, eventually lose the game for a reason, albeit indirect and less effectual, based upon the fact that a player who trades 1 queen for 1 bishop + 1 rook will probably, eventually lose the game. However, such complex exchanges occur rarely in typical games. In fact, the example exchange never occurred between 2 versions of SMIRF that Reinhard Scharnagl compiled for playtesting- 1 using his piece values, 1 using my piece values. So, I was never had the opportunity to see my point proven. Still, I am discontent with this type of subtle inaccuracy. How do the rest of you regard it? Edit Form You may not post a new comment, because ItemID Shatranj Values does not match any item.