Historical Rules · 1 October 2009
Rule 120.4
Official source text from the 1 October 2009 Rules release
If an effect says to "move" a counter, it means to take that counter from the object it's currently on and put it onto a second object. If the first and second objects are the same object, nothing happens. If the first object has no counters, nothing happens; the second object doesn't get a counter put on it. If the second object (or any possible second objects) are no longer in the correct zone when the effect would move the counter, nothing happens; a counter isn't removed from the first object.