The Chessmaster chess engine called The King and written by Johan de Koning of the Netherlands was introduced in Chessmaster 4000. Earlier releases featured a chess engine written by David Kittinger.
The King engine allows users to create new playing styles, also called "personalities", by manipulating several dozen different settings, such as King Safety, Pawn Weakness, Randomness, Mobility and others. Individual piece values can also be adjusted.
Source: Wikipedia, "Chessmaster 4000", available under the CC-BY-SA License.