Conditional (Only show with category)

Hello, I’m hoping someone can point me in the right direction. I’m doing a review site which I have a ranking system in the sidebar. Thing is, I only want it to show for specific categories (IE pc reviews, xbox reviews, etc) and nothing else. If I write a normal non-review article there is a lot of excess stuff in the sidebar.

Is there a method so I can wrap my code with something like..

— The code to conceal below unless it’s a review category —

The ranking system code…
The ranking system code…
The ranking system code…
The ranking system code…

— End the code to conceal below unless it’s a review category —

I hope I explained that well enough. 🙂 Any help is greatly appreciated, I’m pretty much stuck at the moment.