I see no reason why I must first trade my bishop for his on this puzzle:
http://en.lichess.org/training/53525Can someone explain to me why I can't just take the dangling knight?
you think a bit and you will know it
If you can't understand the logic of a puzzle you can always click analyze and turn on local evaluation. Then make the moves that you want and see the computer responses.
I did the analysis and the computer tells that after all the exchanges, white is up a knight.
Correction: Black is up a knight, which is what the player is.
If you just take the knight, he can take the bishop, and then you are both equal (if you take back with your rook, he takes your rook with his rook)
If you take the bishop first, it is also check, and that means he can't defend his white; he needs to get out of check first. So you are a knight up.
Sorry, I should have looked at the local evaluation first. You are a knight up, but the computer still puts you at a much worse position