Zurich 2015 opened with a battle between the champions, and it finished in a draw. Vladimir Kramnik held a relatively sedate Queen's Gambit Declined, Exchange Variation against Viswanathan Anand with patient defense, but the other two games were both livelier and more eventful.
Levon Aronian and Sergey Karjakin contested a Meran, and the latter brought something new to the table. In a position that had arisen hundreds of times Karjakin produced a new move. It might be good one too, but as things transpired Aronian got the upper hand. The Armenian correctly offered a piece sac, and on move 24 had a choice: either take on f6 or give perpetual check. Aronian correctly assessed that the former was a draw and chose the second option; unfortunately for him there was a third choice: 24.Qg6+ Kh8 and now 25.Ng3! The best Black could do after that is an ending two pawns down and some drawing chances.
The last game to finish was the first (and only) game with a winner. For most of the game that was likelier to be Fabiano Caruana, whose extra pawn counted for something. Caruana could have drawn at will, or even reached a pawn-up ending with no losing chances, albeit at the cost of reaching a position where his winning chances wouldn't be especially great either. As sometimes happens, the side who is better persuades himself to keep rejecting decent options that are drawish, and winds up pursuing paths that can lead to defeat. That's what happened here, as Caruana's position collapsed at the end of the time control. Caruana made it to move 41 just in time to realize that he was getting mated by force, and resigned a move later. Just to be clear, Nakamura did a very nice job of keeping things messy. Caruana's desire for more may have been what did him in, but he got a lot of help along the way from Nakamura. (All three games here, with my notes.) UPDATE: The games have been re-posted the usual way, here.)
Because the classical stage will be followed by a rapid stage, these games are scored double. (The classical games are scored on a 2-1-0 system and the rapid will be scored in the traditional 1-.5-0 way.) Here, then, are the pairings for round 2, with the weighted scores in parentheses: