A tactic that wasn't in my repetoire?

  I just played a game in which my opponent did a tactic that wasn't in my repetoire.  The entire maneuver went like this:

 First, he checked me on the back rank, pinning his knight to his rook.  

Second, he checked me with his knight, unpinning his rook therefore discovering an attack on my rook from his rook.  

    I really like this tactic!  In the game it didn't matter, I was already winning, but I'm trying to just focus on the tactic itself.  I vaguely remember this happening to me before but I must not have took note of it.  Now, I know a new trick! =)

   Ah, looking at the game again, I just realized my rook on a8 is defended.  Well, for the purposes of this article, just imagine the rook on a8 is UNDEFENDED and white's maneuver would win him the exchange.