Hikaru makes Sai play Go over internet with the nickname "Sai". Sai is very powerful, and defeats everybody, even Meijin.

I don't know how to play Go very well, but I perceive that a computer algorithm that plays Go can be written easily. And I believe that there must be a lot of Go bots all over the real world currently.

Why doesn't anybody consider the probability that Sai could be a computer bot? I'm very surprised that it is not mentioned even once during the entire series. Is there a reason for this?

  • 5
    Actually, "Go" is an incredibly intricate game with a very high complexity (higher than chess). There are bots that can play "Go", but I don't think there are any that can beat even intermediately skilled humans.
    – Cattua
    Commented May 31, 2013 at 14:41
  • 1
    Just to confirm about the level of computers in go. Bots in go made many progress in the last years (using Monte-Carlo algorithms). At the time of the manga, they were at kyu level (very weak). Today (June 2013), the best bots are at 4 or 5 dan (amateur) level (which is still weaker than an average insei for example).
    – Djaian
    Commented Jun 3, 2013 at 6:57
  • One of the students at the Chinese insei school Isumi visited mentioned he was working on research for computer bots, actually. So it isn't as though they weren't mentioned in the series. Commented Nov 13, 2016 at 18:55

2 Answers 2


Firstly, the manga was released in 1998 which was just about when the Internet was exploding all across the world and the dot-com bubble taking shape. Similarly, the off-the-shelf hardware available at the time was a shadow (think 300 MHz Pentiums) of what is available now. Things were far different back then than they are now.

Secondly, while it might be possible for computer algorithms that play Go to be written reasonably easily, algorithms that seemingly play Go well is exponentially complex. If you consider Deep Blue, the chess engine that beat Kasparov 2-1 (out of six games played) in 1997, it used racks of cutting edge hardware calculating 200 million positions a second, and intricately tuned software specifically built for the purpose by IBM. It didn't exactly overpower him. In terms of board size, possible moves and combinations, Go is far more complex and demanding than chess and it would have been extremely unlikely for any 1998 desktop software to be able to match Go grandmasters of the time.

Lastly, incorporating cheating and other negative elements of real life was unnecessary to the story and would have hamstrung one of the objectives of the manga, that being the aim to popularise the game of Go.


What follows is not a real answer (I believe the accepted answer is correct), but more an interesting side note.

Sai played go on internet. But Sai is a purely fictional manga character.

However, in 2003 - 2004 on a real go server (KGS), a strong opponent appeared and had a 100% win ratio. He won also against some professional players. His name was "Tartrate".

Actually, after some time he lost a few games, but these losses were on time, or occurred during simultaneous games. Note that KGS is not really a "strong" server, so that even if the best players on KGS are professional, they are not the best professional players. But still, Tartrate managed to get an impressive winning streak.

The identity of Tartrate was kept secret, and actually it was only revealed in 2009. So at that time (2003 - 2004 and later until 2009) many players wondered who he could really be. There were many gossips and a web page was created in order to figure out what could Tartrate's real identity be.

Some people even claimed he was Sai (more as a joke than a real hypothesis).

Nobody would believe (seriously) this user was a computer bot. The reason is that at that time the best bots were still at kyu level.

Even today (June 2013), the best bots are at 4 dan or 5 dan amateur level (which is still weaker than an average insei for example).

Also, another interesting anecdote on this topic is "the shodan bet". An amateur player ranked first kyu made a bet of 1000$ with a friend that he would not be beaten by a computer player before 2011. He had to play a series of games against a computer in 2010 and won the bet. However, in 2012 (after the bet deadline), he lost 3-1 against another computer.

The web page about this bet gives some information about computer bots.

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