I really want to know, how “Jose Maria Grau Ribas” manage to score 2100 points with 1 win and 13 lost games ???

And become 16'th strongest player on LG ?

When you signed up, you might have noticed that you were asked what your GO strength was. This determines your initial GO rating. Back in the days when Grau Ribas signed up (and me, and all the other “old timers”), the same was true for Chess: You were asked what your Chess rating was, and this then became your initial chess rating. That's why you'll see lots of players with a chess rating of 1000, which was the lowest you could set then. You'll also see some 2100 rated players with no rated games, as this was the highest you could set.

Also, you may notice that he has really only played one game, which he won. The 13 other games are games which he resigned on the first move. I guess he accidently signed up for the championship, or maybe he signed up to check if the “rating rule” for determining your championship level still was valid. Or something else, who knows…