Sergey Karjakin stunned the chess world by beating champion Magnus Carlsen in the eighth game of their 12-game series, following seven consecutive draws. He thus takes a 4.5-3.5 lead. The fact that he did this while playing black adds to the surprise. Oliver Roeder describes what happened.

It seemed like Carlsen, perhaps hoping to break the stalemate while he was playing white, was pushing too hard for a victory in a game that had been evenly matched, and ended up having to resign after 52 moves.

The advantage in Monday’s Game 8, played on a frigid day in lower Manhattan, swung wildly back and forth between the two players. The game featured back-to-back blunders and a last-second move with the clock’s final seconds ticking down, a scenario worthy of a classic NCAA Final Four game. In the end, Carlsen overextended his reach, wandering into endgame territory more dangerous than he’d realized. Karjakin eventually steeled himself, as he’s done in a number of previous games, and found the winning line.

There are only four games left and Carlsen needs to secure one win to push the match into a tie-breaker system that, according to section 3.7 of the FIDE rules, has increasingly restrictive time limits.

This puts a lot of pressure on Carlsen and he will feel forced to take more risks than he may want to in order to secure a win. Today is a rest day.