A BALK is an illegal act by the pitcher with a runner or runners on base, entitling all runners to advance one base.
To have a balk called there must be a
runner(s) on base. Without a runner(s), many balk provisions are "nothing" or "do overs," including many illegal acts described in Rule 8.05.
Rule 2.00 ILLEGAL PITCH
Rule 7.10 CMT