Both Jdramas, both centre around school, both have unique schools where things only happen there and no where else, both involve a bit of mystery, suspense and high stakes. Chastity high is more uplifting though, Mr hiiragis homeroom is darker.

the main premise isn’t similar, but the two dramas involve prestigious high schools in which poorer female leads are able to attend. in both, dark events occur but in bxtch x rich they are darker.

Similar vibes - both have a a creepy pyschotic kind of character and have a premise that involved crime and death. unlocked is a movie though.

These two dramas have a lot of similarities-
1. mean/evil mother figure
2. an ordinary females introduction into a traditional and prestigious family
3. a mamas boy who has been controlled by his mother
4. suspicious deaths which are investigated
5. very packed full of drama episodes
6. traitors or backstabbing characters
7. an older senior character in the family
and much more
this drama is a lot shorter, amounting to 8 hour long episodes but it is very interesting and i highly recommend it. these two dramas are VERY similar.