Valid pitching appearance?

[mbyron]

Originally Posted by pruett3

Why is 1st base treated differently than any other base?

1. Second base is the farthest from the catcher, which makes it the easiest base to steal.
2. Reaching 2B puts a runner in scoring position, so it's important to the offense to get him there and important to the defense to keep him on 1B.
3. That's why 1B is (almost always) the only base where the runner is held on.
4. More runners reach 1B than any other base.

All of these points apply only to 1B, which explains why it's treated differently. The intent of the rules is to balance offense and defense with respect to advancing a runner to 2B.