Tartrate is a very strong player on KGS. His fabled invincibility has only recently been broken [1]. Opponents left in his wake include Alexandre Dinerchtein 1p, Svetlana Shikshina 1p [2] and "mymy" (rumored to be 6p). While amicable and somewhat chatty, he has chosen to remain anonymous, and will not answer personal questions such as where he comes from or whether he is a pro. Don't bother asking him about his identity.
After a long silence, he made his reappearance in January 2004, continuing his winning streak as expected. His game against Weems 9d attracted over 400 observers.
Tartrate has a message for the online Go world: tartrate STRONGLY suggest that while he is playing games, all the dans (especially higher dans) comment on his game for the community, and is angry and dissapointed when they don't.
In the spirit of good fun, what is your tartrate Number?
[1] On January 16th, 2004, he lost on time against charm (7d, also known as sendol). Quarky game.
http://kgs.kiseido.com/games/2004/1/16/tartrate-charm.sgf
Charm is actually another account of the KGS Teacher "sendol". Sendol seems to have a go school in Seoul, Korea and has recently started teaching on KGS.
Before that, Tartrate did lose a few games on May 22, 2003. Of course, they were part of an 11-game simul, the majority of which he won. However, that impromptu simultaneous test suffered from a serious miscalculation of the time needed to deal with so many games, and casts no reflection on the ability of tartrate to play Go most excellently.
[2] The match between tartrate and Shikshina ("redrose") was an impressive fighting game, with tartrate opening at Tengen. The game involved two large semeais and two large ko fights and ended to a resignation by Shikshina. The game record can be found with the usual KGS kibitz at http://kgs.kiseido.com/games/2003/6/18/redrose-tartrate.sgf.