Changes

Binary books have some important advantages, especially for computer chess engines: space-efficient, fast on accessing and searching, more useful information. At the most simple form, they are just a conversion of above text-opening books into binary, in the ready form for software and save text-binary converting steps. However, the major number of binary top books is built and worked with hash values from [[Transposition|transpositions]]. Often these positions are each position is stored as a hash values to allow fast access. Some opening database formats store with each position as well as value (8 bytes) and some extra information about it. (e.g. such as the number of times occurred, number of games won by white/black / drawn with this position, average/maximum Elo of players playing to this opening position, chess program's success with the position). To save space those extra information typically about 2-8 bytes. For example, [[PolyGlot]] uses 16 bytes for each item, including hash, move, weight, learning values. Items of a book should be sorted by their hash. So when a chess program has to decide on a move, it will look up (by using binary-search) using the hash value of the current position to collect all positions information come with that could arise after moving in the database hash value and then make a decision upon the information given with each position. Depends on designs, an item may take 10 - 16 bytesit.  To build and/or edit those opening books, users need to use special software.