why did this game end?

White resigned after move 42 as there was no way to stop the pawn promotion 

If you go to the game report and go to 'details', you can see the method by which they won

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I'm completely new to chess but also have a question about the ending of a game. Why did this game end in draw by stalemate after I made my laste move: white castle from d5 to c5. It must be some chess rule I don't know about, but should I not have won the game? Black king had no moves left. Please help me out here, would love to learn.

EDIT: uploading my board doesn't seem to work, this is the FEN: 1B3Q2/1k6/8/Q1R5/p2N4/P2P3P/1P3P2/1K3RN1 b - - 4 45

To win a game the opponent's king must be under attack (in check) and have no way to get out of the attack. In your games the opponent's king was not in check and they had no legal moves available, which is a stalemate. Too many queens, or too much power in general, can make it easy to accidently stalemate your opponent. In both games you were crushing your opponent. It would have been better to go for a checkmate without collecting the extra queens.

It goes like this:

The opponent has no legal moves and his king is in check = checkmate = a win
The opponent has no legal moves and his king is NOT in check = stalemate = a draw

In other words, in both of your games I saw, it was your opponent's turn and he couldn't make a single move, but his king wasn't in check, so it is a stalemate.

Here is more if you are interested:

https://support.chess.com/article/682-what-is-stalemate

nklristic wrote: Nethereum wrote:

I'm completely new to chess but also have a question about the ending of a game. Why did this game end in draw by stalemate after I made my laste move: white castle from d5 to c5. It must be some chess rule I don't know about, but should I not have won the game? Black king had no moves left. Please help me out here, would love to learn.

EDIT: uploading my board doesn't seem to work, this is the FEN: 1B3Q2/1k6/8/Q1R5/p2N4/P2P3P/1P3P2/1K3RN1 b - - 4 45

It goes like this:

The opponent has no legal moves and his king is in check = checkmate = a win
The opponent has no legal moves and his king is NOT in check = stalemate = a draw

In other words, in both of your games I saw, it was your opponent's turn and he couldn't make a single move, but his king wasn't in check, so it is a stalemate.

Here is more if you are interested:

https://support.chess.com/article/682-what-is-stalemate

 Thank you, I think I understand, so you are not allowed to force a move that will have the king checked mate if he is not mated at that moment. Never knew that, thx!

You're welcome. In any case, when you see the checkmate is near, you need to make sure that your opponent has legal moves to make if you are not checking his king, or at least try to check his king until checkmate.

White can't successfully stop the pawn from promoting.