Akira Toriyama loosely modeled Dragon Ball on the classic Chinese novel Journey to the West; but also redeveloped it from his 1983 one-shot manga Dragon Boy. He has said that the fighting was influenced from movies by famous martial arts actor Jackie Chan, as he wanted to create a story with the basic theme of Journey to the West, but with "a little kung fu." Since it was serialized in a shōnen magazine, he added the idea of the Dragon Balls to give it a game-like activity of gathering something, without thinking of what the characters would wish for. With Goku being Sun Wukong, Bulma as Tang Sanzang, Oolong as Zhu Bajie and Yamcha being Sha Wujing, he originally thought it would last about a year or end once the Dragon Balls were collected. Toriyama stated that although the stories are purposefully easy to understand, he specifically aimed Dragon Ball at readers older than those of his previous serial Dr. Slump. He also wanted to break from the Western influences common in Dr. Slump, deliberately going for Chinese scenery, referencing Chinese buildings and photographs of China his wife had bought. The island where the Tenkaichi Budōkai (天下一武道会, lit. "Strongest Under the Heavens Martial Arts Tournament") is held is modeled after Bali, which he, his wife and assistant visited in mid-1985, and for the area around Bobbidi's spaceship he consulted photos of Africa.
The Earth of Dragon Ball
, as published in Daizenshuu 4: World Guide
During the early chapters of the manga Toriyama's editor, Kazuhiko Torishima, commented that Goku looked rather plain, so to combat this he added several characters like Kame-Sen'nin and Kuririn, and created the Tenkaichi Budōkai martial arts tournament to focus the storyline on fighting. It was when the first Tenkaichi Budōkai began that Dragon Ball truly became popular, having recalled the races and tournaments in Dr. Slump. Anticipating that readers would expect Goku to win the tournaments, Toriyama had him lose the first two while planning an eventual victory. He said that Muscle Tower in the Red Ribbon Army storyline was inspired by the video game Spartan X, in which enemies tended to appear very fast. He then created Piccolo Daimao as a truly evil villain, and as a result called that arc the most interesting to draw.
Once Goku and company had become the strongest on Earth, they turned to extraterrestrial opponents including the Saiyans (サイヤ人 Saiya-jin); and Goku himself was retconned from an Earthling to a Saiyan who was sent to Earth as a baby. Freeza, who forcibly took over planets to resell them, was created around the time of the Japanese economic bubble and was inspired by real estate speculators, whom Toriyama called the "worst kind of people." Finding the escalating enemies difficult, he created the Ginyu Force to add more balance to the series. When Toriyama created the Super Saiyan (超サイヤ人 Sūpā Saiya-jin) transformation during the Freeza arc, he was initially concerned that Goku's facial expressions as a Super Saiyan made him look like a villain, but decided it was acceptable since the transformation was brought about by anger. He added time travel next during the Cell arc, but said he had a hard time with it, only thinking of what to do that week and having to discuss it with his second editor Yu Kondo. After Cell's death, Toriyama intended for Gohan to replace Goku as the series' protagonist, but felt the character was not suited for the role and changed his mind.
Going against the normal convention that the strongest characters should be the largest in terms of physical size, he designed many of Dragon Ball's most powerful characters with small statures, including the protagonist, Goku. Toriyama later explained that he had Goku grow up as a means to make drawing fight scenes easier, even though his first editor Kazuhiko Torishima was initially against it because it was rare to have the main character of a manga series change drastically. When including fights in the manga, Toriyama had the characters go to uninhabited locations to avoid difficulties in drawing residents and destroyed buildings. Toriyama said that he did not plan the details of the story, resulting in strange occurrences and discrepancies later in the series, including changing the colors of the characters mid-story and few characters having screentone because he found it difficult to use. Since the completion of Dragon Ball, Toriyama has continued to add to its story, mostly background information on its universe, through guidebooks published by Shueisha.
During the second half of the series, Toriyama has said that he had become more interested in coming up with the story than actually drawing it, and that the battles became more intense with him simplifying the lines. In 2013, he stated that because Dragon Ball is an action manga the most important aspect is the sense of speed, so he did not draw very elaborate, going so far as to suggest one could say that he was not interested in the art. He also once said that his goal for the series was to tell an "unconventional and contradictory" story. In 2013, commenting on Dragon Ball's global success, Toriyama said, "Frankly, I don't quite understand why it happened. While the manga was being serialized, the only thing I wanted as I kept drawing was to make Japanese boys happy.", "The role of my manga is to be a work of entertainment through and through. I dare say I don't care even if [my works] have left nothing behind, as long as they have entertained their readers."