JPiere is “Japan + iDempiere”. JPiere is Plugins of iDempiere for Japan and JPiere is iDempiere Distribution(Distro) for Japan. JPiere provides not only Japanese business practice, but also various functions. So, Everyone in the world can use JPiere.
JPiere can update latest iDempiere. So, JPiere don’t need fork from iDempiere. To fork from JPiere is Good idea! But not need fork from iDempiere!