inverarity: (Go)
inverarity ([personal profile] inverarity) wrote2012-07-15 08:24 pm
Entry tags:

Go Go 囲碁! Computers are stupid, but they don't judge

I was not feeling well today, so I didn't go to the go club.

I have long avoided playing computer games because they are time sinks, and computer go proves to be as addictive as any other game. I am still not playing human players online as often as I should, but I am definitely improving against MFOG.


According to MFOG, I am now 9-10 kyu. I think this is an inflation of several stones, since I don't do nearly as well against human players at that rank. But I decided to test its ranking system.

Remember when I first started playing against MFOG, and even at the 18-kyu level (this is the level it plays at if you download the free version) it was often beating me? So, if I am 9 kyu now, I should be able to give it a 9-stone handicap and still win when it is playing at 18-kyu.

It turns out, I can!

Black: MFOG (18-kyu, with 9-stone handicap). White: Inverarity


This was a 9-stone handicap game (meaning I was white, and the computer got 9 stones to start). In the above game, you can see that at 18-kyu, the computer's limited look-ahead ability sometimes causes it to do very stupid things, e.g. that long line of black stones along the upper edge. Even a beginning human player will immediately see after putting down the first stone that there is no escape, but the computer played 9 before giving up. I won this game by 93.5 points. And it wasn't a fluke - I pretty consistently win by 70-80 points. The 18-kyu computer player that was so frustrating for me a few months ago is now a pathetically stupid opponent.

For ranked games, the computer now usually plays against me at the 9-kyu level, and I am winning about half the time. In the game below, I was black, the computer was MFOG (9 kyu), and I won by 10.5 points.

Black: Inverarity. White: MFOG (9kyu)

I know that computer go is a bad habit. I'm going to try to play more human players, honest.

Now, I am going to go do some writing tonight, I swear...

(And oh joy, my wrist has been bothering me lately and it really hurts tonight. I fear either excessive keyboard typing or jujutsu has damaged it.)

ext_402500: (Go)

Computer go

[identity profile] inverarity.livejournal.com 2012-07-17 02:26 am (UTC)(link)
In fact, computer go has been extensively studied and is an active area of research for AI scientists.

Besides the depth problem that [livejournal.com profile] tealterror0 mentioned (just using brute-force look-ahead algorithms, go is exponentially more complex than chess), there is the fact that go is strategically more complex than chess as well. Heuristics for evaluating the value of a move in chess can use fairly well-defined metrics (material, positional advantage, etc.) based on the current state of the board. But in go, a stone played on one side of the board can have implications on the other side of the board 20 moves later, and any move might be good for profit but poor for influence, or vice versa, which means whether or not it's a good move depends on which strategy the player is pursuing.