When "Dragon Ball" began, it was loosely based on the classic Chinese novel "Journey to the West", with Goku being Sun Wukong and Bulma as Tang Sanzang. It was also inspired by Hong Kong martial arts films, particularly those of Jackie Chan, and was set in a fictional world based on Asia, taking inspiration from several Asian cultures including Japanese, Chinese, Indian, Central Asian, Arabic and Indonesian cultures. Toriyama continued to use his characteristic comedic style in the beginning, but over the course of time this slowly changed, with him turning the series into a "nearly-pure fighting manga" later on. He did not plan out in advance what would happen in the series, instead choosing to draw as he went. This, coupled with him simply forgetting things he had already drawn, caused him to find himself in situations that he had to write himself out of.