File Extension SI3

File type: Index File

The SI3 file type is primarily associated with 'ChessDB' by Dr. David Kirkby. ChessDB is a database program used for storing chess games. A ChessDB format database consists of three files: .SI3 (index file); .SN3 (name file); .SG3 (game file) (those 3 are needed to make one database). These are all binary files. Some complete databases are held on the ChessDB web site. At the time of writing, one database (called 'huge') has over 3.5 million games. Other files used in ChessDB are: .PGN (Portable game notation, which is used in lots of chess programs, so is not unique to ChessDB); .EPD (Extended Position Description); .SSO (Search options file); .SOR (Repertoire file); .DAT (used on four files - engines.dat history.dat options.dat and recent.dat) to hold configuration information. All are text files.

When windows gives you an error message saying that it
"Cannot open SI3 files", this means either:

A. You need to identify a program that can open the file
B. Or your registry may be damaged

In both cases it is strongly recommended that you
run a free scan for registry errors.