So close in terms of ideas you'd almost think that one inspired the other. Basically a highschooler and a gangster switch bodies and the highschooler with the soul of the gangster then becomes the new cool kid cause of his gangster-powers of beating people up.

Both very melodramatic dealing with identity as heavy themes and involve a lot of revenge of good characters vs evil characters.

It's about the exact same era. Just featuring a focus on different historical people but essentially both try to keep true to the historical real events within Goryeo.

Both feature a guy dressed as an animal who is really being perceived as an animal in its universe but also has to function in human society.

In both movies an older male character takes a suicidal younger male against their consent. In both movies a bond starts to develop between the male characters.

Fujoshi no omoi was the inspiration for the Bibari & Rui skits in Picaru no Teiri. They both feature the comedians Yoshimura Takashi and Ayabe Yuji doing a BL skit.

Both have Japanese boygroups in it who have to fight against sketchy criminal groups to keep their group safe. They both have a bit of a ridiculous premise although JAM goes way further with it.

Both are shows with the main couple being actors from Johnnys Entertainment. Both are a BL and a Japanese drama.

Both movies have male leads with light bleached hair. In both cases the male lead stands out from the rest of the classmates around them and in both theres highschool romance.

Both about firefighters and medical staff helping patients. Except one focusses more on diverse topics while The Flaming Heart is more concentrated on romance. Both dramas focus on the human struggles of being in charge of protecting lives.

Similar as it contains a fake marriage. Differences being that in the Korean movie its a lesbian couple that arranges the fake marriage with a gay couple. Meanwhile in the Taiwanese movie its a lone woman being convinced to play fake wife for a gay couple.

Both include an artificial boyfriend for a human girl. So both have a robot guy in them and focus on romance.