Hello,

I came across this position from Peter Svidler vs Alexei Shirov's game.

Houdini 2.0b's recommended move was 21.b3, and the move was evaluated as +0.16.

Interesting, Svidler made a better move than Houdini. Svidler did 21.Rxc8 and Houdini evaluated Svidler's move as +0.27, which is better than Houdini's original suggestion.

After looking at the position, I still don't understand the reason behind Svidler's Rxc8. Does anybody has insight behind this super GM's move?

Thanks.

Here is the complete game.

hankas duudddeeee, send me some tactics puzzles.

hakas why am i getting so bad

 all of a sudden?

I'm using Houdini_15_w32 and I'm getting recommended 21.Rxc8 with a value of +0.27.  As for the move itself, I haven't analyzed it; it's late now.  zzzz

@ratatouie: There is a tactics trainer at chess.com. Please help me conserve my grey matter.  

hakas, so what is ur question.

Better yet, why are you using ratatouie's traditional titling format to ask it?

Lol.

I am telling you the guy is a trendsetter. Soon everybody will start posting like this:

hello hankas here how's everybody doing i just drop by to say hello cheerios hankas out

yo dawg, I herd u liek- okay, can't think of a good meme. Nevermind.

To answer the OP, I guess we could solve this by assuming the move was correct, then thinking backwards.

The most likely reason white exchanged rooks would be that white wants to prevent black from doing the same. The difference it makes is that white's queen would get to stay in the same spot instead of having to recapture where the rook was. As a result, white would be giving up control of the c-file, and gaining more control of different diagonals.

Most of white's pieces seem to be heading towards the kingside, so it doesn't look like the c-file affects white's plans as much. More importantly, white's bishop already controls the dark diagonal, so a queen might only get in the way. Finally, I think the reason has to do with white's a and b pawns. A rook exchange forces black to recapture with the queen or bishop. (Note that if black takes with rook, white wins a pawn with dxe5. Currently, the rook is defending e5 with the threat of a revealed attack using the bishop.) In the given position, both queen and bishop are guarding white's b-pawn, thus a rook exchange essentially gives white a bit of indirect control over that pawn.

Nachtwulf - the queen is defending the pawn though - what I'm wondering is why black played Bxc8 instead of Rxc8. If Svidler knew black would play Bxc8, of course he would play Rxc8 in an instant. It prevents a rook from getting to the c file for a few moves, removes defense from the b pawn, and most importantly prevents Rxc1 Qxc1 Rc8 with tempo.

I missed the fact that black's queen is currently defending e5. Previously, I had thought that the rook had to stay there to guard the pawn, but clearly that is not the case. Just roughly looking at the resulting position, if black recaptured with the rook, white would be controlling the central files, while black would be controlling files to the side. I obviously don't play anywhere near the level of the players involved, but that would be my best guess.

My guess is that black wanted to move his bishop to b7, but that plan was prevented when white replied with Bd3 threatening the pawn at b5.

Why didn't black ever play Nc4?

And no one comment here on the game as it is not finished. I just wanted to show the idea.

I decided to delete the game I posted so I don't get accused of cheating.

Rxc8 is baffling, Bxc8 even more so... neither GM seems to think the open c -file is worth fighting for. I have no insight except to say, -- I don't get it, but I'll bet they're doing it right.

With a bishop on b1 there is no way for a rook to penetrate, and didn't nimzowitz say that an open file doesn't matter if the rooks can't penetrate. Rxc8 looks better anyways because it controls c4, an outpost for the knight. I still don't understand.

I actually spent quite a bit of time looking at this position.  My assumption was that there would be some way to take advantage of the bishop's position after 21... Rxc8 22 de de...but I couldn't really find anything.