How can I tell if a chain has a master link? I need to remove the chain on my internal-hub cruiser to clean it (i.e., no rear or front deraileur), and I'd rather not remove my back wheel if I can avoid that. What do I look for to find the master link?

Edit: Unfortunately, there's no differently-colored pin, and running my fingertips over the chain (both sides) didn't help. Do I have a one-piece chain?
Usually when I talk about or hear someone use the term 'Master Link' they mean something like this:


They are links that can be seperated without the use of a specialized chain tool to push a pin through the rollers.  There are others besides those shown, one of the more common being an SRAM Power Link which looks like this:



If you don't have a link like those that is visibly different what you most likely have is a Shimano style HG or IG chain that requires the use of a chain tool to remove a pin from the roller.  Frequently the pins will have a little indentation where the chain tool seats.  When you break the chain with a chain tool, you normally reassemble it with a replacement pin that looks like this:



After the chain is back together you break off the insertion portion of the pin with a pair of pliers.