Opening Explorer can use multiple data sources to present its infromation. The following sources are available to consult about the current position:
- Database - the whole database is presented as a tree of moves available together with the statistics from the database itself. This source has the powerful automatic filter option, see the Database source section for details.
- Filter (Last search) - the current database filter is the last search and is presented as a tree of moves with statistics from those filtered games only. This source is useful to examine player or opponent opening repertoires or specific openings or any other filter you can create, see the Filter source section for details.
- Local opening book - the local opening book included is built on Grandmaster games and you can see the moves and statistics for those moves played in Grandmaster games. Only established moves are shown.
- Online books - the HIARCS Chess Server provides very strong opening books with the latest opening theory and novelties. Depending on the product type you can have access to a GM or GM+ opening book with the latest moves and statistics presented. Book subscribers get access to additional online opening book content.