Do you capture the Bishop, when you have a knight in the center??

HI all,

I realize I have a number of "basic doubts" in some positions, and I'm seeking help.

Today's one is: assume you are black, and have a knight on e4. White plays his bishop on d2. The question is if, generally, the correct approach would be to capture the bishop. I'm not sure what to do, since, again generally, I believe there is a wide consensus in considering a bishop slightly more valuable than a knight, so this assumption would tell me to capture it.

At the same time, a knight on e4 is certainly a very advanced and powerful piece. If it is supported by a pawn, then it is even stronger.

So, can someone help me to "build" some basic understanding about what to consider, how to read the position, things to factor in, to make the right decision? I believe there's not a unique answer to my question, but at least when it is your turn to move and decide, what is your train of thoughts?

Thanks!

AG

Try to look at whether it is a closed or open position. Take the bishop if it is a wide open game. Keep the knight if it is a closed position or most of the action will be on one side.

In this position black captures Nxd2

Purely objectively speaking, I think most of the time, knights will want to capture the bishop. But of course it will depend on a lot of different factors. In the position posted by #3, the black squared bishop is very strong, as it's attacking the black kingside. But imagine a position where white has pawns on e3, d4 and c3, black has a pawn on d5 and a knight on d5. The bishop on d2 there is horrible, because it's just looking at his own pawns and there is not quick way to change that. There you wouldn't want to take the bishop on d2. So maybe that's the easiest answer: look at the bishop: if it's blocked by its own pawns, then don't take it. In most of the other cases, yes, you'll want to take it.

Of course, chess is much more difficult than just this decision. It really does depend on the position after all. I can also imagine positions where black is attacking. Then you might not want to trade pieces. So, it depends. If you have a specific position in mind, you can post an example to get some feedback and maybe a bit more feel about when you do want to exchange and when not.

The question you ask has a more general application: at what point do general considerations and "rules" give way to analysing the position in front of you?

We all want to "study" and build a "repertoire" of ideas that eliminates the need to think. Alas, we cannot do without thinking at the board.

As you become more experienced, the better will be your decisions as whether to go with the "rule" or analyse what happens if if you "break" the "rule".

When starting chess, the player who observes the "rules" will do well. The exceptional player is he or she who knows when to "break the rules". Suffice to say, observing the "rules" is the way for most of us to go most of the time.

More generally, the specific question you ask is about mobility. Will the knight persist in its strength, or will the subdues bishop increase as the game goes - according to your best analysis. A bishop is usually better to have than a knight, but what about the pawn structure?

If you have a space advantage then there is the "rule" about not exchanging pieces so as to keep the other player cramped. As your experience increases, all these considerations will come into play. The you make a judgement call and make a move one way or another...

Each case is different.

In most cases, probably, yes. The "betterness" of the bishop is somewhat permanent while the "betterness" of the knight can be lost.

In this case (edit: I didn't notice the position example is from tygxc and not from OP until after I wrote this), it's also yes, especially since the king will be stuck in the middle after recapturing.

There could be other cases which are "no," for example, I noticed after you capture the bishop, and White recaptures, he can possibly sac his other bishop for two pawns and then his queen has some nice checks, and maybe could find a sneaky way to win back some material--but it's not good enough in this case, so he won't do it.

So, in most cases yes, and in this case yes, but not always.

The AVERAGE value of a Bishop is slightly greater than the AVERAGE value of a Knight.

But that doesn't mean that in you should always (or even typically) play NxB.

First, a Knight posted in the center is probably a better piece than an AVERAGE Knight, just like the Bishop is. That levels the playing field somewhat.

Second, capturing the Bishop often means trading off a Knight that has moved three times (Ng8-f6-e4xd2) for a Bishop that's only moved once. Two tempi lost. Is the Bishop-for-Knight exchange worth losing two moves right in the opening? Always?... or just sometimes?

Third... and this is trivially obvious... each exchange of pieces reduces the number of pieces left on the board. This automatically changes the in-game value of certain advantages and disadvantages. A Space advantage tends to become less and less relevant with every trade of pieces. A Pawn advantage becomes more and more threatening with each trade of pieces.

So it is NOT just a question of "Youtube says Bishop = 3.5, Knight = 3; so trade them off". Not at all. Chess is not that simple.

I wouldn't attach much signifigance to the particular example given above... in that line in the McCutcheon, Black's NxB is pretty well forced. He's going to lose a center Pawn otherwise.

... so saying "Black always plays NxB here" is just a way of saying "Black doesn't like giving away his center Pawn for nothing". It says nothing about the value of N vs B in this position.

In the board example shown...I'd take the bishop.

While I might think about the relative value of bishops vs knight, and while I might even be tempted to think about the extent to which good bishops and bad bishops alter that evaluation...I just don't think that black has any alternative. If the knight leaves the b2 bishop alone where else can it go? what else can it do? If it doesn't go somewhere or do something it will be taken.

While the black pawn advancing to F5 is tempting...with all the possibilities of a queen capturing a pawn on g6 with check and tempo ( and still influencing E4)...there's an en passant reply here... and yes that does in turn allow a possible black queen ( now developed and attacking) sitting on f6 ...one way or another that knight is going to die...it might as well go with a bishops scalp on its belt!!

Theres no rule that fits every situation. In end game...a bishop that is only on one color can become useless. Does capturing the bishop give you an edge in development? Does it keep the king from castling? Do what makes sense at the time. ... It will really depend on circumstances.

Here is another example. Black takes on d2, either immediately, or after ...Bxc3 bxc3.

Many thanks for the many reies and suggestions, each one contains valuable material. As far as example in #3, I think in that case the capture is almost forced, since otherwise the knight is attacked more times than defended, and it does not have an escape square.

A perfect example to be honest. After Bxc3, bxc3? nobody is ever capturing the bishop on d2 as it's completely blocked in by pawns. Black probably should continue with a move like ...f5 or ..b6 followed by Bb7 to take control of the light squares, most notably e4. But after Bxc3, Bxc3 then we definitely are taking the bishop pair away from white with Nxc3.

@15

Here is an example game. White recaptures 6 bxc3. Black should have taken 6...Nxd2, as 6...O-O allowed to save the bishop with 7 Bc1.