The following was the position before the final move in an online tournament game I played this afternoon. Before looking at the answer, see if you can figure it out:
I believe all beginner and intermediate player should make it a priority to master tactical recognition and calculation. I have been thinking about this lately, and although it is not very profound (many instructors and masters also agree with this), I am reminded of just how important it is as a foundation to more advanced strategic planning and concepts.
This shows up when I am studying a position, thinking about infiltrating weak squares of trading off my "bad" piece for his "good" piece and I miss a mate-in-two. Often, the opportunity doesn't present itself again once it is missed.
In any case, here is the move: 30...Rd2! threatening the bishop on c2 as well as the pawn on g2 (which would lead White giving up his queen to avoid the checkmate with the Black queen entering the scene on h3). My opponent resigned here.
Tactics! Tactics! Tactics!