Sabian, in a 24-page article, reviewed many existing methods and came-up with his own methodology, inspired from previous trials. He created a program that generates random chess positions, then calculated average mobility in thousands of positions approximating the relative piece val. Another progress has been the use of powerful engines: an approach presented by Grandmaster Larry Kaufman has allowed the evaluation of the relative piece values in many situations, e.g. the bishop pair. List of fairy chess pieces The following table shows some game pieces of unorthodox chess, from fairy chess problems and chess variants (including historical and regional ones), and the six orthodox chess pieces. The columns "BCPS", "Parlett" and "Betza" contain the notation describing how each piece moves. The notation systems are explained above. 0–9 – A – B – C – D – E – F – G – H – I – J – K – L – M – N – O – P – Q – R – S – T – U – V – W – X, Y, Z See also Chess variants Correspondence chess Movement of the orthodox pieces Orthodox piece names in different languages Penultima—a chess variant in which fairy pieces are invented for each game References Bibliography Link. Web pages 154 pieces from old Shogi variants. . §§: "Piececlopedia" & "Articles on Pieces". Also: "My Chess Variants". §§: "Variant Chess Games"; "Introducing Variant Chess" & "Simple Chess Variants" [PDF] (2010) §§: "Geometry: Theory of Moves"; "History" & "Other Pieces". External links Piececlopedia An extensive list of fairy chess pieces, their history and movement diagrams Who is Who on Eight by Eight Compiled by Ivan A Derzhanski, shows also piece values Generic Chess Piece Creation System Easy ways to estimate piece values A Guide to Variant Chess: All the King's Men Fairy chess pieces Chess variants Chess problems