How many books are there in the Blue Sky series?

According to the watermelon video query, there are two plays in this series. The first one is Yang Jiajiang, a costume drama produced by Hong Kong ATV, supervised by Yang, directed by Hu, and starring Jin Chaoqun, Zhen Zhiqiang. The second part is Pearl Flag and Blue Sky with Game Stories, which is a TV series produced by Hong Kong ATV 1994. The film, which is produced by Yang and starring, tells the story of Di Qing and Emperor Xixia.