Why do Grandmasters make weird retreating moves with their bishops?

So, I noticed when watching some grandmasters play (airthings tourney, just in general really) that whenever a bishop is attacked, they move it out of the way. Even when it’s on a square that it’s already protected. Why? Knights and bishops are worth the same, and in a recent game (kasparov topalov, don’t remember the year) the bishop was on the second rank, and the knight jumps in to attack it, and then it’s moved to the the first rank??? Like, that would be a bad trade for kasparov, giving up an outposted knight for a bishop like that, but you know. One person here is a grandmaster and one isn’t. Why do masters do moves like this?

Because it might be attacked 

Bishops are better than Knights

Rerouting is definitely something GM’s do and is hardly seen on my level (1500-ish). I never do it. To much focused on not losing tempi and the other reason is that I simply don’t think ‘hey, what a pitty my bishop is there and not there’.

To reroute them to a different diagonal. The position might require pressure to be exerted elsewhere and they need a different path to do that.

Huh it didn’t load. Weird.

 

 

What the heck chess.com

 

I looked real quick. I’m assuming you’re looking at 18. Na5 Ba8. Here’s my stab at it:

Black already has a somewhat weak king, as a lot of the pawns that usually offer protection have already moved forward. Black wants to preserve the light-squared bishop so that black can at least contest the weaknesses on the light squares (b7, c6, d5) — black feels this is more important than letting the bishop fall for a knight. Furthermore, black maybe senses that he will have to play a defensive game soon, so black would like to retain a bishop, which is better at defending than a knight. If black allows his only remaining bishop to be captured, the only minor pieces he has left are knights, which have a difficult time defending squares in this position.

That’s how I see it myself anyway

So it’s only not loading for me....great.

Ah, okay then. I personally think that the trade is good, trading off that knight for the okay bishop, and that the knight would be useful in the attack. Moreso than the defending bishop.

If the light squares around the king are weakened, how do we take advantage of that? The light squared bishop has 2 pawns blocking it’s fianchetto spot, and we have 2 attacking pieces (R&K). By the time we get our pieces to the king, won’t it be too late?

Because they felt that their bishop was more valuable than their opponent's knight, in that position.

There's no strict rule about the relative value of bishops vs knights. It depends on the position itself.

Sometimes, a player should welcome an exchange of his bishop for his opponent's knight.

Other times, a player should avoid it.

It depends on the pawn structure, the critical squares, and any potential tactics that may arise.

I don't agree with the general motto that bishops are worth more than knights. That's a mindset built on the static value of pieces. (Pawn =1, Knight =3, Bishop=3.3, Rook=5, Queen=9)

Those are static values. But chess positions aren't static; they're dynamic, always in flux.

As such, the value of pieces depends entirely on the position, as their positional/tactical worth continually changes, throughout the game.

Try clicking on the edit button of the post and repost.

Yeah, its a GENERAL motto, but its a bit misleading, bishops are better in open positions, or positions with open lines, knights are better in closed positions, these are also usually true, but sometimes a knight can be really blocked in, or a bishop can be the piece that holds the position together

Thank you!

I went looking more more examples and I found em. Weird bishop retreating moves.

 

 

That’s Sjugirov, Vitiugov 2021, btw

Why does it have to retreat tho? It’s protected, and if pawn takes you have a half-open file for the rook. Isn’t that good?

And if you don’t want your pawns doubled, take with the queen. And the knight can reroute to c6, no?

White is arguing that black's knight is misplaced on the edge of the board.

So white takes away black's option of exchanging it away, which would force black to lose tempo in the future, by having to move it again, to bring it back into the game.