Why today's Ding_Liren-Nakamura_Hikaru 35th move is a blunder


I'm new to chess.

Why 35. Kf1 Bd8

is a blunder.


It leaves white with more active pieces.  Putting the rook there would likely lead to a rook trade with both sides having decent activity and a draw being likely.  Hikaru was afraid of something or other that if your a computer engine, isn't an issue. 

Really the move is only a blunder in the GM sense and its a bit hard to learn from.  That said, perhaps you can see how Hikaru's pieces become cramped, defensive and not coordinating well.  


As computer moves go it is hard to see what Nakurama was concerned about after Rd8 it looks fairly natural. 

Which move is a blunder
It is hard to understand the move 35…Bd8. Maybe he intended to play 36…Nf6, threatening both the rook on d7 and the h5 pawn, and before he could play Nf6, he had to remove the bishop from g5 because of 37. f4 (after 36…Nf6), winning the bishop. It turned out that after 35…Bd8, Stockfish gave a 3.26 point advantage to white. From the game link above, Stockfish gave 35… Rd8 as the best move.
That’s great news

Sometimes new players misunderstand... they think all bad moves can be explained by showing a few (or many) follow up moves that result in losing some pieces or checkmate.

High level games have moved far beyond counting pieces... yes the number and type of pieces are usually equal (not always) but high level games are more concerned with the activity of the pieces. This means a move that results in permanently less active pieces can be a blunder, even though there is no series of moves that will prove pieces will eventually be lost. You might need 100 or thousands of different variations to prove white always comes out ahead in pieces or checkmate, but the players didn't need to calculate a single one of these to understand black is worse, because again, it's all about piece activity. They calculate to verify whether white maintains a lead in activity or not, but they don't calculate trying to find out how to win pieces.

In fact most experienced players will immediately understand Bd8 is optically bad... meaning it just doesn't look right. Looks are often deceiving, but in this case it's (apparently) even worse than it looks and white is already winning.


So you might ask why Naka would play a move that a player 1000 points below him immediately says looks odd. Well as @artnj said, Naka was probably afraid of something else in the position, and eventually settled on the move Bd8 as a necessary evil (or he believed it was useful in spite of being ugly or etc).

Turns out he was wrong and the move was bad, but that's how chess goes, it's a tough game and we all make mistakes.

But yeah, there's no single line we can show you that will definitively illustrate why it's bad.

nMsALpg wrote:

In fact most experienced players will immediately understand Bd8 is optically bad... meaning it just doesn't look right. Looks are often deceiving, but in this case it's (apparently) even worse than it looks and white is already winning.

It is worth pointing out that Robert Hess and Daniel Naroditsky (both only about 200-300 points below Hikaru) immediately thought it was a transmission error as Bd8 is optically bad.

To expound on the answer to the OP, there are 2 categories of blunders: tactical and positional (also called strategic).  Tactical blunders are what cost us sub-master players most of our games (it is extremely rare for a game between 2 sub-master to change direction for positional reasons - we usually blunder material).  Bd8 is an example of a positional blunder.  As @nMsALpg pointed out, there is no line where White does X, Y, and Z and wins a piece.  Instead, you start to notice that Black's pieces have no moves.  Everything is tied down (passive) and Black cannot improve his position nor can he defend his weaknesses.  White, on the other hand, can continue improving his pieces until Black gets into zugzwang.

I am not sure if Hikaru has uploaded his review of this game, but I am curious why he went with Bd8 as everyone and their brother thought he would play Rb8 where pieces are likely to come off and it is likely they end up in an bishop endgame where his pawns were on the opposite color of most of his pawns while Ding's would have been locked on the same color as his bishop.  The likely result there is a draw, but only Hikaru could win it due to having control over both color complexes.  In fact, if it has simplified down to that, I suspect Ding would have simply offered a draw at move 41.


35...Bd8 loses so it is an error. 35...Rd8 would have held the draw.


Nakamura's thoughts on game here There was a curious echo with 18...h6 instead of 18...RXR followed by Rd8 which would have drawn very easily. It is a rare case were I would have played better move than a player that can calculate much better than myself, just on positional grounds.  Practically 18...h6 lost the game more than later move, because black's position became much harder to play.