Some programs score certain terms differently for the side they are playing and for the opponent. Most often the big terms, like king safety, passed pawn evaluation or mobility are scaled in some way. Whilst it might be argued that this idea runs counter the definition of chess as a zero-sum game, it also allows greater freedom in shaping the program's playing style. Richard Lang's programs were famous for their asymmetry in evaluation and forward pruning [1] , which emphasis safety (rules like 'do not start a wild attack, but worry a lot if the opponent does so') [2] .
Henry Moore - Helmed Head N° 2 [3]

See also

• Odd-Even Effect
• Opponent Model Search
• Parity Pruning
• Tempo

Publications

• Ingo Althöfer (1992). On Asymmetries in Chess Programs. ICCA Journal, Vol. 15, No. 1
• Javier Ros Padilla (1994). Estimating Asymmetry and Selectivity in Chess Programs. ICCA Journal, Vol. 17, No. 1 ^[4]

Forum Posts

1997 ...

• asymmetry by Andrew Tridgell, rgcc, August 12, 1997 » KnightCap, Parity Pruning
• Re: Junior's long lines: more data about this... by Don Dailey, CCC, December 26, 1997
• Genius' asymmetric-search by example: TRY yourself by Thorsten Czub, rgcc, December 30, 1997
• Asymetric king safety by Tom King, rgcc, March 13, 1999

2000 ...

• Parity of depth level and evaluation by Claude Le Page, CCC, June 13, 2005

2010 ...

• evaluating color agnostic terms by Alvaro Cardoso, CCC, October 15, 2013
• Different eval for white/black by Matthew Lai, CCC, January 05, 2015
• Asymmetrical evaluation by Laurie Tunnicliffe, CCC, May 24, 2016 » Odd-Even Effect
• Symmetrical evaluation and endgame by Hamfer, OpenChess Forum, June 02, 2016 » Tempo

References

1. ^ Genius' asymmetric-search by example: TRY yourself by Thorsten Czub, rgcc, December 30, 1997
2. ^ Kaare Danielsen (1987). The 7th World Microcomputer Chess Championship, Rome, Italy, September 14-20, 1987. ICCA Journal, Vol. 10, No. 3 » WMCCC 1987
3. ^ Henry Moore - Helmed Head N° 2 (1950), Bronze on Marble slab, Art Museum, Bochum, North Rhine-Westphalia, Germany, part of The Industrial Heritage Trail of the Ruhr area, Photo by Gerd Isenberg, October 30, 2016, see also 2011 image of the sculpture at Art Gallery of New South Wales from Wikimedia Commons
4. ^ ICCA Journal, Vol. 17, No. 1 by Jos Uiterwijk, rgcc, May 02, 1994

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