A more thorough explanation:

Definition: Blank bar is a legal term used in history to describe a plea in bar that a defendant would use in a trespass action. The purpose of this plea was to force the plaintiff to provide a specific location where the alleged trespass occurred. It was also known as a common bar.

For example, if a farmer accused a neighbor of allowing their livestock to graze on their land, the defendant could file a blank bar to require the farmer to provide the exact location of the alleged trespass. This would help the defendant prepare their defense and determine if the accusation was valid.

Another example could be a case where a property owner accused a construction company of damaging their property during a construction project. The defendant could file a blank bar to require the plaintiff to provide the exact location of the alleged damage.

These examples illustrate how a blank bar was used to force the plaintiff to provide specific details about the alleged trespass or damage. This information was crucial for the defendant to prepare their defense and determine the validity of the accusation.