Why Chess Will Likely Never Be "Solved": A Look at the Unfathomable Complexity

The idea that chess, a game with a finite board and pieces, could be "unsolved" often raises eyebrows. After all, machines can beat the strongest human players. But the reality is far more intricate than that. While computers have achieved incredible strength in chess, the very nature of the game and the definition of "solved" are what make a true solution so elusive, possibly forever.

The Magnitude of the Problem

Imagine building a perfect roadmap of every single possible chess game, where each path leads to a known outcome (win, loss, or draw) assuming perfect play from both sides. The sheer number of possible games – estimated at around 10^120 – is so vast that it dwarfs even the estimated number of atoms in the observable universe (roughly 10^80). Even the number of possible positions is estimated to be around 10^44, according to Chess Stack Exchange.

This astronomical figure is the core reason why brute-force calculation, the method used for simpler solved games like tic-tac-toe, fails spectacularly in chess. Even if every single atom in the universe were a supercomputer, it would still take an impossibly long time to map out every single game variation.

"Solving" Chess: A Deeper Look

The term "solved" itself can be interpreted in several ways.

Weakly Solved: Proving which of the three possible outcomes (White wins, Black wins, or Draw) results from perfect play, without necessarily revealing the optimal strategy itself. Even this has not been achieved. While the prevailing expert opinion suggests a draw with perfect play, it remains unproven.

Strongly Solved: Developing an optimal strategy for every possible position, enabling perfect play from any point in the game. This level of solution would require storing and accessing an unimaginable amount of information, far beyond current and likely future computational capabilities.

The Human Element: An Unpredictable Factor

While AI engines may play at superhuman levels, chess isn't just about optimal moves on a board. It involves psychology, predicting opponent's reactions, and adapting strategy. The "best move" might not be the most mathematically sound one, but rather the one most likely to exploit an opponent's weaknesses or psychological state.

Even in an hypothetical scenario where chess was weakly solved, and it was revealed that with perfect play the game results in a draw, this would not diminish the fascination of the game. The complexity of chess makes it impossible for a human to memorize the solution, even if one existed, meaning that human ingenuity and understanding of the game would remain crucial for success.

A Relevant Game: Demonstrating Human Endurance in Complexity

To illustrate this blend of complexity and human endurance, consider the following game. While not the absolute longest in terms of moves (that honor goes to the 272-move Billy Fellowes vs. Peter Lalić game from 2024), it's a monumental achievement in human concentration and calculation in a world championship setting:

Why this game demonstrates the limits of solving:

This game, drawn after 269 moves, showcases the resilience and tenacity of human players even in complex endgames. While a computer might eventually find the optimal sequence, human players, operating under time pressure and without infinite calculation capabilities, must make choices that navigate not only the objective strength of the position but also the psychological landscape of the game.

The endgame phase, particularly with only a few pieces remaining, is often where the sheer depth of calculation required in chess becomes most apparent. Even with powerful engines, determining the absolute "best" moves and the path to a forced win or draw can still be challenging. In this game, the players navigated a rook and pawn scenario for an extensive period.

The game ultimately ended in a draw due to the 50-move rule. This highlights that even without a definitive "solution," the game has mechanisms to conclude when progress towards a decisive result becomes stagnant.