"Though I'm not entirely sure..." Lu Zhao began slowly. All three pricked up their ears. "Judging by what happened to Jin, these... these books are very likely 'Edicts,' also known as 'Yin-Yang Books.'"
Chen Bing and Chen Xue exchanged a look, both somewhat puzzled, seemingly unfamiliar with the concept.
"Edicts? Yin-Yang Books?" Only Jin Jiuyao's expression sharpened, as though something had occurred to him. "Those things that use layers to transmit information?"
Chen Xue asked, "What's an Edict? Why does that sound a little familiar?"
Lu Zhao was about to explain, but seeing Jin Jiuyao looking as though he had something to say, he said, "Since you're so eager to show off, you explain."
Jin Jiuyao grinned. "Hehe, sure."
"With Yin-Yang Books, whatever you write in the yang book can appear in the yin books."
"There can be just one yin book, or lots of them. Since they were first invented by the 'Oracle,' they were called Edicts. But because orders go out from one end and get received at multiple ends, people later started calling them 'Yin-Yang Books' more often."
At this, understanding dawned on Chen Xue. "Oh! Now that you mention the 'Oracle,' I remember. A teacher mentioned it when I was studying, but since it wasn't on the exam, I didn't bother remembering it. I just listened to it like some unofficial history..."
Lu Zhao nodded. Since it had come up, he would say a little more. "The earliest records of Edicts appeared in the Codex. According to legend, a being called the 'Oracle,' one of the 'First Apostles,' created them to make it easier for their companions to explore the Black Sea."
"The method for making Edicts has always been recorded through various channels, but they need layers as a medium to transmit information. And layers