When was the last time he lost? What is his unbeaten streak at?
I think he generally loses on a regular basis like other GM's.
In june, last year, at the Tal memorial.
Casual_Joe, this is not the case for Carlsen
The longest unbeaten streak in top level chess (in terms of games playes) belongs to Mickail Tal, who was undefeated for 95 consecutive games played over the period of 1 year (from october 1974 to october 1975).
The Tal after 1972 was different from the Tal of 1960.
The manner of Carlsen's losses in the Gashimov Memorial was atypical. Usually Carlsen loses because he pressed too hard to win an even or drawn position or - more rarely - an opponent will outplay him from the opening.
In this tournament, it began with his draw against Karajakin in the 3rd round. He was winning, but rushed to win a piece in the ending for two passed pawns, which proved enough counterplay to hold. He could have maintained his positional advantage with ...Nf4 just improving his position, not hurrying. Then against Caruana in his Berlin Defense, he recaptured ...Be6xd7, which ceded the d-file and especially d5 to White for a long time, when ...Ke8xd7 would clear the way for the Rh8. That one in particular seemed unnatural.
Then against Radjabov, he responded to Black's ...Ne4 with Nc3xe4, which is one of the first things White players learn NOT to do vs the KID, opening the f-file and inviting Black to fight for the diagonal b1-h7 which can be unpleasant. From there Radjabov just cashed him in, very efficiently.
Carlsen doesn't make that sort of positional error often, in the last three years if it was once a year it might overstate it. Here he does it in three consecutive games, and in the rest of the games he scores 6+ 1= 0- .
I read in a comment somewhere that he was sick, never saw it confirmed, though. But that would fit with three days of uncharacteristic play.
Yes, but no player is ever as good as at the end of his greatest streak of performance. Tal remained a Candidate-level contender facing much stronger average opposition than he had in his youth, and adopted a more positional style.
In fact, he was back in the top ten from 1971's first official list, and was equal second with Karpov in 1973, remaining in the top ten and again reaching second in the world to Karpov in 1980, but soon thereafter had another bout of health problems and did not reappear in the top ten until 1983. By 1985, health dogged him once more, and he didn't make it back into the top ten again, I think.
He had more sustained success as a mature player.
I was referring to Tal's style of play, Estragon. I am aware of Tal's success in the 1970s including his great year in 1979. Montreal and Riga.
All the players with long streaks without a loss in top chess naturally tend to be of the cautious sort, like Capablanca, Old Tal and Kramnik. Even though the latter two never were ranked #1 during their streaks, the stronger players took more risks and won more games, scoring better results, but with a loss here and there. Kasparov or Fischer never got close to anything reminding of what Tal and Kramnik did, even though their results were more impressive. So the question is how much the unbeaten streaks really matter, apart from being an interesting curiousity.
The unbeaten streaks of Capablanca and Kramnik reflect their cautiousness, but the fact that the two longest unbeaten streaks of all time both belong to Tal is somewhat unexpected. He underwent a major change in style between 1960 and 1972.