In my last blog post we looked at a really interesting endgame involving a pair of Bishops vs. a pair of Knights with pawns on both sides of the board. This time around we’re going to examine the same idea, but we’ll simplify it a bit: we’ll look at a single Bishop against a single Knight.
In both cases, though, the underlying principle remains the same: in endgames in which both players have pawns on both sides of the board, Bishops tend to be better than Knights. It’s simply a mobility issue: Bishops move farther than Knights. A Bishop can not only zip quickly back and forth across the board in a single move (shuttling from the Kingside to the Queenside and back whenever necessary) but also just plain controls more turf than a Knight. On an open board, a Bishop controls seven squares at its worst, while at its best a Knight controls only eight squares:
A Bishop can easily pick off opposing pawns and/or support and defend friendly ones on both sides of the board. But Knights are slow and often have to struggle just to defend friendly pawns on one side of the board — never mind trying to reach the opposite side in time to be effective.
Using a program like ChessBase 10, you can finds literally thousands of Bishop vs. Knight endgames. Here’s just one that I discovered, a game from 2009 played between grandmasters at the chess World Cup (and, by the way, the Black player isn’t the former World Champion of the same name):
Meier,Georg (2653) – Petrosian,Tigran L (2615) [D81]
World Cup Khanty Mansiysk (1.2), 22.11.2009
White is winning as he’s a pawn ahead, but Black can still make a fight of it as long as he tries to keep material on the board. White can’t advance the e-pawn to create a passed pawn (e5 is controlled by both of Black’s pieces) and his Rook is tied to the e4-pawn’s defense. Black’s best strategy is to try to keep White’s pieces tied up and play for the “frustration draw”.
The Bishop retreats, but now Black decides to do something ill-advised: he’s going to trade Rooks. He’d have been far better off playing 28…f5-f4.
28…Rxe4 29.Rxe4 fxe4
The material is now equal and neither player has a passed pawn. White, though, still has the advantage because (you guessed it!) his Bishop is better than a Knight with pawns on both sides of the board. And Black’s a-pawn is hanging…
30.Bxa7 Kg7 31.Bd4+
The Bishop hustles back and checks the King, picking up a tempo.
31…Kg6 32.Ke2 Kf5 33.Ke3 Nh6 34.h3 g4 35.a4
Here’s a fundamental reason why the Bishop is better than the Knight. White’s Queenside pawns, supported by the Bishop, can advance and create a passed pawn. Meanwhile the Bishop (if necessary) can still help out on the Kingside. Black’s Knight, less mobile, can only be active on the Kingside.
35…gxh3 36.gxh3 Ng8
Black loses more time as he tries to reposition his slow Knight to a more active spot.
37.b4 Ne7 38.Bc5 Nd5+
This just drives the White King to a better square. Black is really scrambling here: he can’t let White create a Queenside passed pawn, he needs to try to create his own passed pawn, and he really can’t afford to lose any more material. It’s just plain impossible for the Knight to be everywhere at once.
39.Kd4 Nf4 40.b5 Ke6
Black is hopeful that his King can dash White’s plan to gain a passed pawn. But now the e4-pawn is dangling, and White’s in a happy place: he has a choice of winning moves.
[41.Kxe4 would also win. 41…Nxh3 42.f4, then Black really has nothing better than 42…Nxf4 43.Kxf4 Kd5 44.Be7 and, to use that really annoying phrase, “the rest is a matter of technique”. But, honestly, White’s game pretty much plays itself from here.]
41…Kd7 42.Kxe4 Nxh3 43.f4 h5 44.Kf3
Black is just plain sunk. Sooner or later he’s going to have to trade his Knight for White’s f-pawn, the White King will then snap up the h-pawn, and a White Queenside pawn (aided by the Bishop) will promote. In fact, Rybka4 (with the help of the Nalimov tablebases) finds a forced mate in fourteen here. Fire up your tablebases and see for yourself!
Black resigns. 1-0
So what does all of this mean to you? When you’re in a late middlegame or early endgame, knowing that Bishops tend to be better than Knights with pawns on both sides of the board will help you determine whether or not a particular minor-piece trade is a good idea. If you have Knights, try to trade them for your opponent’s Bishops if possible, but also try to keep your Rooks (or Queen) on the board (as seen in the game above). If you have the Bishops, try to hang onto them instead of trading them for an opponent’s Knights.
On the other hand, if you have two Bishops and your opponent has a Bishop and Knight, try to swap off the same-colored Bishops so you’ll have a straight one Bishop vs. one Knight endgame.
Want to learn more about minor-piece endings? ChessCentral carries Karsten Mueller’s FritzTrainer Endgame DVDs. ChessCentral also offers an extensive line of chess pieces, boards, software, and gift items (Christmas is coming soon!)
Have fun! — Steve
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