[iopq]

Yes, but that's not an indicator of complexity. It's an indicator of the skill of other players.

You can make an argument that the game tree complexity is immense, but that's because people prefer to play on 19x19 boards. 9x9 boards are similar to chess in game tree complexity, and had in fact strong computer engine play ten years before AlphaGo

[slightwinder]

No, I mean that it mainly is an indicator that complexity for the players does not only come from the rules, but also the explored game tree and the level you get from other players. There are many games similar to go, in terms of simple rules and hidden complexity, but none of them are as successful as go, because they simply lack the history and success of go.

It's a strange feedback-loop that certain things become more successful because they are successful, which enable them to grow into their deepness and fully embrace it, reeling in more people who prefer this.

[NineStarPoint]

I would definitely argue that complexity comes from the number of meaningful options available to the player, not strictly rule complexity. Simple rules can lead to complex situations. This has little to do with the skill of the players involved, even two amateurs playing Go are faced with constant decisions that will effect the course of the game. It is indeed the 19X19 board where placement is allowed anywhere therein that gives Go it’s complexity.

[valyagolev]

it's not about other players, it's about the ability to understand what's going on at all. go is not a "simple game with a lot of depth", even reading the board is a skill