Opposite bishops

No, not the Church of England and its troubles with the question of whether women should be allowed to be bishops, but chess endgames, with rival bishops moving respectively on black and white squares. Traditionally, the fact that the bishops can play, as it were, past each other increases the possibility of a draw, as indeed do the enhanced possibilities of mutual blockades.
 
Nevertheless, great masters such as Nimzowitsch, Capablanca, Botvinnik, Smyslov and Karpov have been able to demonstrate that skilful handling of such situations may in fact lead to one side having, in effect, an extra piece if the enemy opposite bishop can be sidelined.
 
At the recently concluded tournament in Wijk aan Zee, Magnus Carlsen twice proved that he has joined the elite group of filigree artists who can achieve wonders when opposite bishops are present. It is interesting to note that, in both games, the black bishop plays virtually no part in proceedings at all.
 
Carlsen-Karjakin; Wijk aan Zee 2013
 
White has the advantage here due to his active pieces, the weakness of f7 and the terrible situation of the black bishop 67 g4! hxg4 68 h5! Rh1 After 68 … gxh5 69 f5, the white initiative is too strong, e.g. 69 … h4 (69 … Kg8 70 f6, planning e6) 70 f6+ Kg6 71 Rxf8 and although the black pawns look dangerous the bishop can come to d5 and the rook to the h-file which will keep them under control. 69 hxg6 fxg6 70 Re6 Kh6 71 Bd5 Rh2+ 72 Kg3 Rh3+ 73 Kxg4 Rxd3 74 f5 Re3 75 Rxg6+ Kh7 76 Bg8+ Kh8 77 Kf4 The white pawns are far quicker than Black’s and the black bishop remains a bystander. 77 … Rc3 78 f6 d3 79 Ke3 c4 80 Be6 Kh7 81 Bf5 Rc2 82 Rg2+ Kh6 83 Rxc2 dxc2 84 Bxc2 Kg5 85 Kd4 Ba3 86 Kxc4 Bb2 87 Kd5 Kf4 88 f7 Ba3 89 e6 Kg5 90 Kc6 Kf6 91 Kd7 Kg7 92 e7 Black resigns
 
Carlsen-L’Ami; Wijk aan Zee 2013
 
Here White has the problem of trying to make his extra pawn count. It will be difficult to use his queenside majority to actually win the game but Carlsen finds a plan which involves using it as a diversion in order to mount an assault on Black’s kingside — in particular the vulnerable pawn on g7. 47 Bd2 a4 48 Rxe5 Rxe5 49 b4 Bb5 50 Be3 h5 51 Rc7 Kg6 52 Ra7 Rd5 53 Kg3 Rd3 54 Bc5 Ra3 55 Bf8 Rxa2 56 Kf4 Kh7 57 Rxg7+ Kh8 58 Kf5 Rc2 59 Kxf6 a3 60 Ra7 a2 61 g3 Rc6+ 62 Kg5 Kg8 63 Bc5 Ba6 64 Bd4 Rd6 65 Ba1 Black resigns
 
Carlsen triumphed at Wijk aan Zee ahead of Aronian and Anand. This augurs well for his prospects in the world qualifier, set for London in March.