About Lomonosov tablebases

About 7-man endings

7-man tablebases were calculated in 2012 on Computer Science department of Moscow State University. Calculations were done on supercomputer named Lomonosov. So they were named Lomonosov tablebases. Generation of tablebases is an important step as in chess theory and practice so in improving of retrograde analysis algorithm.

The tablebases contain the exact evaluations (draw or moves to mate) for all positions with no more than 7 pieces on the board. The total number of positions in the tables – more than 500 trillions (500 000 billions). The real number of similar positions is several times more, but part of them can be obtained from others by mirroring and rotating of the board, so there is no need to keep them on disks.

Imagine how many hard drives are essential for providing the evaluation and the best move for any position. 1000 disks and Petabytes of data on them? Fortunately there is a possibility to compress data and there is need only in keeping 100 TB of data. Compression also was not a simple task compared by complexity with calculating of tables.

Even with high level of compression the size of tablebases is tremendous and is not available for storing them on typical desktop computer. So this site was created for providing online access to server with tablebases.

Site supports the following functions

Setting up 2-7 pieces position on the board, receiving its exact evaluation and the line of optimal moves leading to mate or draw.

Viewing positions shared by other users.

Browsing statistical data for any ending. Statistics informs about lengths of the longest mates in the endings and corresponding positions. Also statistics keeps information about compression sizes and ratios.


If you will registrate on the site you will be able to save favorite positions in your personal cabinet, share positions with other users, vote for them, to discuss endings on the forum. But to access random 7-man positions you need to become VIP-member by entering access key.

VIP membership

Access to any 7-man position via site is currently available only for VIP-members. This limitation allows to avoid heavy load of the server. Also it is important to note that tablebase hardware support is rather expensive. So creators of the site would like to receive some income to continue to support the server.

To become VIP-member you need access key. The key can be obtained in case of purchasing one of two programs Aquarium or Chess Assistant. The other ways is to pay $20 for this.

Pay attention that there is no need for VIP-membership to access to 7-man positions that are records for every ending and to the positions shared by VIP-members.

Free Android application

One more way to access 7-man tablebases without having a key is to use Android application.

Search for Lomonosov Tablebases or use the direct link.