To open up an Earth Fire Sky Furnace, if one is a cultivator of the Cave Heaven Realm, then one only needs to use Great Dharma Power to hook and stir the earth fire and forcibly create a Heavenly Furnace.
Apart from the time it consumes, there is nothing particularly unusual about it.
But even if one does not have the abilities of a Cave Heaven True Master, it is not that there is no way at all.
For instance, that Dragon Country sea boat of Zhang Yan's was originally crafted by the Yin Family of the East Sea, and was likewise refined in an Earth Fire Sky Furnace. That furnace was made after the Yin Family's ancestor found a naturally formed earth grotto, then used a clever method to draw the earth fire up.
This was to borrow the force of the land's configuration and make it serve one's own use.
Though there were still many unsatisfactory aspects, with this one furnace in hand, it caused untold numbers of sects to envy them.
