It's so far, so good for the favorite in the 2016 Women's World Chess Championship, as Hou Yifan dispatched Mariya Muzychuk pretty convincingly on the white side of an Open Ruy. Hou's 14.Bf4 was a rare move, allowing Muzychuk to damage her (White's) kingside pawn structure in return for the bishop pair and some kingside attacking possibilities (notably f3-f4-f5).
The idea may have been for one game only, but in this case it proved effective. Hou also wisely avoided any immediate commitments to a kingside attack, and moves like 16.Rfd1 and 19.a4 forced Muzychuk to burn a lot of time worrying about White's queenside possibilities as well. Muzychuk's decision to play 19...Nd8 was ill-advised, and although Hou's inaccurate 26th move gave Muzychuk one chance to save the game, Black was overwhelmed from that point on. Muzychuk managed but a single cheapo at the end of the game, which came after Hou's 32nd move won a piece. (My analysis of the game is here.)
The players have Friday off, and resume on Saturday and Sunday.