The Blue Square is a symbol on snowboard/ski slopes which is used to denote moderate difficulty. Generally, blue square slopes are a bit steeper than the green circle slopes, but are free of the drop-offs, rugged terrain, and moguls of a black diamond slope. These designations are highly subjective and vary from place to place - for instance, there are 'intermediate' runs at Sugar Bowl which are steeper and more challenging than 'black diamond' runs at Steamboat.

For new snowboarders, it is often a good idea to find a fairly easy blue, or more difficult green slope to learn on, once you have the basic balance down. This is becuase without any speed or slope, it is quite difficult to learn the fundamentals of boarding; or even to stay on your feet in some cases.