The Eight Diagrams Furnace is a prop in the The Journey to the West, which is used by the old gentleman in Taishang when making alchemy and treasure. There are six sacred fires in the furnace, one of the four skyfires.
Most of the top equipment in The Journey to the West, a demon novel in the Ming Dynasty, came from the Eight Diagrams Furnace (such as Ruyi Golden Hoop, Nine-tooth Nail Rake, Zijin Bell and other weapons). Grandfather also put the Monkey King into the furnace and burned it, resulting in a pair of golden eyes. The Monkey King walked down the gossip furnace and fell into the mortal world, forming a flaming mountain. Hon Hai 'er, the son of cattle, practiced samadhi in this mountain.
How time flies! I didn't realize that on July 49, the old man was ready. Suddenly, one day, the stove was turned on to pick up Dan. The Great Sage was rubbing his eyes with a runny nose when he heard the kitchen stove ring. When he suddenly opened his eyes and saw the light, he couldn't help it. He jumped out of the Dan furnace, fell into the gossip furnace and came out.