Changes

The book identification code of the [[Opening Book|opening book]] in [[IsiChess]] (commercial [[MS-DOS|DOS]] version) had all book lines defined in a [[Portable Game Notation|PGN]]-like textfile with a descriptive name and ECO code associated, much more than the 500 determinative ECO lines and full of transpositions, merged into an opening tree similar to a persistent [[Transposition Table|transposition table]] indexed by the [[Zobrist Hashing|Zobrist key]], keeping not only a list of possible moves from the current position, but also a list of different predecessor moves aka indices to the different opening lines. Its [[IsiChess#Book Editor|book editor ]] has not only an opening tree view, but also a list view of opening lines where multiple lines with different last moves and possibly ECO codes may appear, leading to the current position. [[FILE:IsiChessBook.jpg|none|border|text-bottom]]