1. e2e4  1... c7c5  2. g1f3  2... g7g6 As far as I know, this is the first time Caruana has played this variation, which can be called Hyper-Accelerated Dragon. Some new ideas have been found in this line, which has recently been revived and used by strong chess players. One of its experts is GM Abdusattorov, although he plays it in rapid games. 3. d2d4 The two big alternatives are 3.c3 and 3.c4. (This last move can lead to a transposition later.)