Today I am going to talk about the sealing a weakness by physically blocking lines. It is really a nice theme which beginners often fail to see; when your opponent tries to exchange the blockading piece often you get a passed pawn, a better pawn chain or a nice outpost for a piece.
Here are a couple of examples of this:
Seirawan against Yussupov in 2000
Q: Black has a weakness on c6 but which is not accessible to White in the near future. Could you formulate a plan for Black using the theme discussed above?
Hint: You can seal that weakness by placing a piece on c4. This kind of idea often arises in the QGD Exchange pawn structure.
Solution: Black can bring his knight to c4 via f8-d7-b6 and c4 which not only seals the weakness on c6 but gets a nice outpost.
Here is the rest of game:
20…Nf8 21.Nb3 Qa3 22.Qc1 Nd7 23.Rc2 Qa8 24.Ne1 Nb6 25.Nd3 Nc4 26.Re2 Qc8 27.Nbc5 Rce7 28.Rfe1 Qf5 29.Kg2 h5 30.f3 Qf6 31.a4 bxa4 32.Nxa4 h4 33.Nac5 Qg6 34.e4 hxg3 35.h3 Bxc5 36.Nxc5 dxe4 37.Rxe4 Rxe4 38.Nxe4 Nd6 39.Qxc6 f5 40.Nxd6 Rxe1 41.Qc8+ Kh7 42.Qxf5 Re2+ 43.Kg1 Re1+ 44.Kg2 Re2+ 45.Kg1 Qxf5 46.Nxf5 Rf2 47.Nxg3 Rxf3 48.Kg2 Rd3 49.Ne2 Kg8 50.h4 Kf7 51.h5 Kf6 52.h6 gxh6 53.Nf4 Rxd4 54.Kg3 Kf5 55.Ne2 Ra4 56.Ng1 h5 57.Kh3 Kg5 58.Nf3+ Kf4 59.Ne1 Ra2 60.Nd3+ Kg5 61.Ne5 Ra3+ 62.Kh2 Kf5 63.Nf7 Rd3 0-1
The next example is one of my favourites and a really instructive one:
Janowski against Capablanca in 1916
Q: What will you do with your damaged pawn structure on the queenside? Try to formulate the plan.
Hint: Capablanca uses weak pawn to support the c4 square.
Solution: Black first supports the b5 square by playing 10…Bd7! and then slowly gets the pawn push to b5 in order to bring his knight to c4 via a5-c4 route. The whole game is really instructive and has already been annotated by Nigel D here.