What is the origin of the idiom "playing field" and when to use it?

The idiom "playing field" has its origin in sports, where a level playing field is necessary to ensure fair competition between teams or individuals. The phrase can be used to refer to any situation where the conditions or circumstances are perceived as being fair or unfair to different participants. It is often used in discussions of social justice and equality, where the goal is to create a level playing field for all members of society.