Nobunaga was first called the "Six-Day Demon" in the third year of Yuangui (1572). Because of Hideyoshi's intelligence operation and Nobunaga himself once called himself the Six-Day Demon. At that time, Takeda Shingen was about to go to Beijing, Nobunaga wrote a letter with the signature "Nobunaga, the Lord of Tiantai", and Nobunaga wrote a reply to Nobunaga with the signature "Nobunaga, the Six-Day Devil". It can be seen that Nobunaga and Nobunaga are very aggressive with each other. For Xin Xuan and others, they can become Buddhas after death; But for nobunaga, only what you can see now is true. Nobunaga does not agree with the idea of enlightenment after death, which is probably why Nobunaga called himself the "Six-Day Devil" at that time. Nobunaga himself has some frightening parts, similar to Cao Cao.