I don't know which (if either) of the two variants is regarded as official, but I think it is highly probable that the version with two horizontal bars is the original form of the yen sign, as this symbol was almost certainly created by analogy with the pound (�) and dollar ($) signs, both of which had two bars in their original forms (though both also have variants with one bar).
S�amas � Br�g�in ----------------
