No, Shinchan is not based on a real story or a real person. Crayon Shinchan is a fictional Japanese manga series written and illustrated by Yoshito Usui. The series made its first appearance in the year 1990 in a Japanese weekly magazine called Weekly Manga Action. An animated television adaptation began airing on TV Asahi in the year 1992 and continues till date, with over 1200 episodes.
The main character, Shinnosuke “Shin” Nohara, is not based on any real human, as claimed by many Shinchan fans on the internet. The character was created by Yoshito Usui. Usui drew inspiration from his own childhood experiences, observations of children in his neighbourhood in Kasukabe, Japan and things he wanted to do as a child but couldn’t due to social norms.

Plot Summary
The story revolves around Shinnosuke “Shin” Nohara, a bold, mischievous and shameless 5-year-old kindergarten boy living in Kasukabe, Japan. There is no continuing storyline. Instead, each episode follows Shinchan’s daily antics as he drives others around him crazy with his crude jokes, unfiltered behaviour and wild imagination.
Shinchan loves flirting with pretty girls, obsessing over his favourite superhero Action Kamen, performing his infamous dance moves and causing trouble at kindergarten, home and public. Shinchan’s long-suffering family includes his short-tempered but loving mother Misae, overworked salaried father Hiroshi, baby sister Himawari and fluffy dog Shiro. His kindergarten friend circle comprises of boastful Toru Kazama, crybaby Masao, tough girl Nene and quirky Bo-chan.
Shinchan is associated with innocent but perverted jokes on adults and complete disregard for social norms, family dynamics and Japanese culture.
Misleading Fan Theories
While there are multiple fan theories behind the origin of Shinchan, a particular theory has gained immense traction among the fans of Shinchan. In fact, this hoax has been circulated widely through social media posts, blogs and articles.
As per this theory, Shinchan is based on a real boy named Shinnosuke Nohara who died in a tragic accident while saving his younger sister. His mother Misae slipped into depression due to the loss of her son and drew him with crayons, thereby inspiring the series.
This is a highly emotional tale and widely shared online. However, it is a fake story, with no factual basis. Yoshito Usui himself never mentioned any such story during his lifetime.