What do you mean by joining the club? What is the explanation?

Watch the top. It's called initiation. Banners have merits of initiation, so they are called initiation banners. Or, it is called hanging a banner high, so that its end touches people's heads, which is similar to initiation, so it is named initiation. Starting from the printing wheel when the Holy Prince ascended the throne, the ceremony was solemn and there was a flag, which Buddhism imitated as Buddhism. In ancient times, it was carved with copper plates. Lao Hua Yan Jing Dian Juan 270 (Big Nine? 572 Middle School): "For example, the son of a runner made him a king. The runner, the Saint Prince, ordered his son to take out four sea waters from the treasure of the white elephant, hang up curtains, put all kinds of solemn buildings on them, and hold golden bell perfume, which is called the Emptying King. It is also recorded in the Secret Collection that the compassion of the Buddhas means irrigation, and the world is enlightened by flags, which is based on the merits of flags. First, he was the king of the wheel, then he became a Buddha, so that the Buddha fruit was enlightened, so he was named after the fruit. p6855