You can choose between the following opening databases:

• Huge Book
  This database contains about 16.3 million moves from chess grandmaster games and gives you a survey what ever has been played by strong human chess players. The size of the opening database is about 1 GB.
• Shredder 9 Book
  This database is included in the Shredder 9 and Deep Shredder 9 distributions. It contains about 1.2 million chess moves. Each move has a value associated with it. Its size is about 95 MB.
• Shredder 10 Book
  This database is included in the Shredder 10 and Deep Shredder 10 distributions. It contains about 1.3 million chess moves. Each move has a value associated with it. Its size is about 96 MB.
• Shredder 11 Book
  This database is included in the Shredder 11 and Deep Shredder 11 distributions. It contains about 1.3 million chess moves. Each move has a value associated with it. Its size is about 97 MB.

An chess opening database or opening book is a huge chess database. For each chess position in the database a list of moves is stored. For each move the following information is available:

• Value
  A value that could be associated with this move. Shredder uses the values from a-f. “a” is for a good move, “f” for a bad move.
• Games
  The number of times this move has been played.
• Perc.
  The result of the games in percent in which this move has been played. The number indicates how many games were won when playing this move.
• Elo
  The average Elo rating of the players playing this move.
• Perf.
  The Elo performance achieved when playing this move.
• Year
  The average year in which this move has been played.
• Wins/Draws/Losses
  The number of won, drawn and lost games with this move.