This weekend, a friend of mine brought a “Go” board to a party. I’d heard a lot about this notoriously complex and ancient game. Most recently, it was in the news because a computer finally beat a master Go player.
This triumph of computer programming illustrates just how hard Go is. Computers were regularly beating chess masters decades ago, yet Go is still challenging. What makes this game so unique?
GO vs. Chess
On the surface, Go seems simpler than chess. There is only one type of piece and a handful of rules, unlike chess’ array of different pieces (each with their own rules).
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The strategy of the game is an emergent property of these simple rules. It’s a strange truth that, mathematically, very simple rules (like those of Go) can create nearly infinite complexity.
To understand how, consider the consequences of a move. In chess, a given move might capture up to one enemy piece. Except in rare cases, this means the immediate fallout of a move is comprised of just two things: (1) a piece moves (2) another piece is removed.
In Go, the consequences of an action are potentially much further-reaching. A single “capture” can remove dozens of pieces from the board at once. It’s theoretically possible to reverse even the biggest of leads with a single move.
Mathematics of Moves
It might seem like having more pieces (in Chess) means more possibilities, but the opposite is actually true. Because the rules that govern each piece are restrictive, it means the number of legal game positions are limited. Incidentally, this is why experts can spot a legal Chess board at a glance.
Just how many moves are there in Go? In a standard 19×19 board, the number of possible configurations is 208 168 199 381 979 984 699 478 633 344 862 770 286 522 453 884 530 548 425 639 456 820 927 419 612 738 015 378 525 648 451 698 519 643 907 259 916 015 628 128 546 089 888 314 427 129 715 319 317 557 736 620 397 247 064 840 935. Yes, that’s one number.
The Role of Human Intuition
Curiously, while Go hides a lot of mathematics, many players rely on intuition and aesthetics.
The game works on the metaphor of “capturing territory.” It’s actually quite easy to learn to read a Go board because of this metaphor. The objectives and rules make a certain intuitive sense. Legend has it that ancient Eastern leaders have even challenged military opponents to a game of Go in lieu of a war.
This sort of intuition speaks to the ability of the human mind to internalize simple rules. It’s another example of how this intuition can work even better and more accurately than the most advanced computers.