Chess Terms

# Tablebase

Is chess a solved game? The answer is... partially. And tablebases are why. Read on to find out more about this very important endgame tool.

## What Are Tablebases?

A tablebase is a computer-calculated database of every endgame position with a certain number of pieces, which tells the user if correct play results in a win, a draw, or a loss for either side. The current limit is seven pieces, for both White and Black combined, including the kings. Thanks to tablebases, the theoretical result of any position with seven or fewer pieces that can appear in a game is known.

## Why Are Tablebases Important?

A tablebase is the most efficient way of knowing which side, if any, has the decisive advantage in an endgame. The usual way for a spectator to determine the advantage is by referencing the computer evaluation. In many endgames, however, this evaluation is ambiguous or uninformative. Here's an example.

In the above screenshot, the computer evaluation (the bar visible on the left side of the screen) shows Black with an advantage of 0.8 points. However, you can see on the right-hand side that the position is actually a draw, so long as White finds one of the correct moves.

Tablebases can do this in any position with seven or fewer pieces! During the longest game in world championship history (game six of the 2021 World Championship), GM Ian Nepomniachtchi captured GM Magnus Carlsen's h-pawn on the 115th move of the game, leaving seven pieces on the board. From that point on, until the game ended 21 moves later, spectators could tell instantly, even before the next move was played, whether the position was a win for White (or Black) or a draw.

At that exact moment, the tablebase revealed that the position was drawn. However, on the 131st move, Nepomniachtchi made the decisive mistake. Carlsen found a winning reply and Black resigned soon thereafter.

In the very long run, tablebases may be the way to solving chess completely. While seven pieces are currently the limit, all eight-piece positions are being solved right now, and nine-piece positions would be next. It gets exponentially harder to calculate with each piece added, but there is no theoretical reason there can't eventually be a 32-piece tablebase.

## Can You Study Tablebases?

Yes! In the Chess.com Analysis feature, any eligible position has a "Tablebase" tab that allows you to see the best-play result of every legal move in the position.

Once there are only seven pieces left, the Tablebase tab will replace the Openings tab in the upper right.

## Conclusion

Now you know what tablebases are, why they're important, and how to access them on Chess.com. Next time you play an endgame with seven or fewer pieces, check a tablebase on our Analysis page and see the results!

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