White KB?

In this sentence from a lesson in Chess Mentor, what does White KB mean?

"In his haste to grab the valuable White KB, the great Reshevsky, Fischer's main American rival for decades, hasn't noticed the unpleasant surprise Bobby has in store."

Thanks,

Steve 

king's bishop, the one standing at f1 at the start of the game.

The white KB is the f1 bishop (the light square bishop).

Oh.  OK.  That make sense now.

I also see things like: Rac1 and Nbd7     

I'm guess it means the following?

Rac1=means Rook on file a at the beginning of the game, move to c1

Nbd7=means Knight on file b at the beginning of the game, move to d7

Thanks,

Steve

No, when you have Rac1, it means that you have 2 rooks that could go to the same spot, so you name either the file or the rank that they are on, that way you can tell which one moved there.

When it says Nbd7, it doesn't mean the knight that started on the b file, it just means that the knight is currently standing on the b file, or rather, did so before you moved it to d7. The extra b instead of just Nd7 is used when 2 (or more) knights can move to the same square.

Thank you for simplifying what I said.