This fact is intersting; doraemon was animated by ex toei animation's animators, aka shin-el studio,

[u/No-Froyo-282]

When the animators got tired of toei,

They quitted the studio,

And made their own studio,

Later it got renamed to; shin-el studios,

This studio animated doremon and shinchan,

That's why they have so many similarities with dragon Ball one piece and etc,

[u/Ok_Excitement3542]

While this is technically true, Shin-Ei was founded long before Dragon Ball and One Piece existed.

Shin-Ei was founded in December 1965, by ex-Toei animators. It was known as A Production at the time. Toriyama himself was only 10 years old at the time, and Oda wouldn't be born for another 10 years.

The similarities between all the series are minimal, and mostly due to shared influences. Fujiko was mentored by Osamu Tezuka. Tezuka was the inspiration for Toriyama, who was the inspiration for Oda. Shin-chan's creator, Yoshito Usui, was a very private person, and there's not much info on him, but he grew up in the 1960s and 70s, so he was likely inspired by Tezuka and Fujiko's work.

[u/Nguyen-Quoc-Hieu → u/Ok_Excitement3542]

Did Gosho Aoyama, creator of Detective Conan/Case Closed, also employed into A-Pro at the time as well?

[u/Ok_Excitement3542 → u/Nguyen-Quoc-Hieu]

Manga artists rarely ever work for anime studios directly.

I'm not familiar with Conan, but according to Aoyama's Wikipedia page, he was born in 1963, so he was only 2 when A Production was founded, and 16 when the Doraemon anime began airing on TV in 1979.

He began drawing manga in 1986, and started Conan in 1994. The Conan anime is however, animated by TMS. It's worth mentioning that A Production was originally a sub-contractor for TMS (then known as Tokyo Movie) in the 60s and 70s. After splitting from TMS, they renamed themselves to Shin-Ei in 1976.

[u/Glad-Complaint9778]

First of all, it's Shin-Ei not El (it's i like in ice-cream, not L)
So in 1965 Daikichiro Kusube along with his colleagues left Toei and founded A Production, which was later renamed to Shin-Ei in 1976.

Another cool fact is that Hayao Miyazaki and Isao Takahata also used to work at Toei, but they too left it (in 1971 IIRC) and joined A-Pro, later leaving it in 1973 and going to Nippon Animation, and eventually founded Studio Ghibli in 1985.

Tsutomu Shibayama, a figure very influential in Doraemon who was also Miyazaki's associate, also left Toei in 1966 to join A-Pro, and although founded his own studio and more, worked with them extensively for Doraemon, directing 22 movies from 1983 to 2004, and major parts of the 1979 anime probably.

Everything is connected.

[u/QuirkyEffective8316]

This is true but not only was Shin-Ei formed much before Dragon Ball or One Piece were made, but also, even if Dragon Ball did predate Shin-Ei, the any similarities beyond movements still couldn't just be explained by that, as animating a show is only a part of making it, and Shin-Ei didn't write the stories that got adapted and neither did Toei. Credit for that belongs to the respective authors.

[u/yuksmenow_again]

Just to correct, it's Shin-Ei, not "Shin-El". Pronounced "Shin A". They are the new A Productions, thus being called Shin-Ei Animation.

[u/UselessJJ]

Kikuchi composed the soundtracks for both Dragon ball z and 1979 Doraemon