Right now, there's a player lurking in the depths of the online Go scene that is laying waste to some of the best players in the world. It's called Master, and nobody knows who it is.
Update: The identity of the mystery account has finally been revealed - you can read all about it here.
The account is simply called "Master", and since the start of the new year it has made a habit out of trashing some of the world's best Go professionals. It's already beaten Ke Jie twice, who is currently the highest ranked Go player in the world. AlphaGo, incidentally, is #2.
Not that the ranking stopped him from being battered, mind you. A European professional Go player, Ali Jabarin, wrote on Facebook that Ke Jie was "a bit shocked ... just repeating 'it's too strong'". Jabarin wasn't sure whether the player was AlphaGo or not, but he was certain that an AI was behind the mystery account.
By January 3, the number of probably-but-we-can't-officially-say AI sanctioned beatings had risen to 41-zip. There's a few signs that it might not be an all-AI account, though. Jabarin received a polite message on New Year's declining a match, and a post appeared offering around $US14,000 to any professional player who could beat it.
Given AlphaGo's beatdown of Lee Sedol last year, the initial speculation blamed Google for the carnage. But given the way Google so prominently publicised AlphaGo's matches, it's unlikely they would just unleash a champion-beating AI on the world of online Go without so much as a post. And even if they were to do so, it's already been noted that Google already has two accounts reserved on the most prominent Chinese and Korean online Go servers.
The suspicion, then, is that another autonomous Go legend has appeared. While AlphaGo was getting all the praise last year, another company launched a deep learning Go bot with the support of the Japanese Go association.
The makers estimated it was about 500 ELO points behind AlphaGo at the time - although the bot is also a known quantity, plays under a different alias and reportedly has a different playstyle. South Korea's amateur Go association has been developing an AI as well, and it wouldn't be surprising if the developers of that unleashed their efforts online just to test the waters. Tencent has been developing a Chinese Go AI too, as has Acer.
But this is all purely speculation, as there's been no official confirmation as to the mystery player wrecking online Go. The only thing anybody knows for sure is that the world's best Go players have been getting slapped around by something. Possibly someone, but probably something. If you'd like to review the slaughter, I've embedded one of the matches against Ke Jie above. There's also a good post on a German Go site with embeds of Master's first 41 games.
Update: Master's winning streak has finally been ended - although not through entirely legitimate means. Master racked up 51 straight wins, only for the internet connection of professional Chen Yaoye to time out. The timeout meant that the 52nd game on Master's record will be recorded as a tie, therefore breaking the winning run.