Both dramas are Taiwanese crime dramas. In both there is a group of individuals that investigates a case that is resembling an old case. The whole time the story questions of what happened in the current case and also how it is linked to the past case. In both dramas there is a culprit that plays with the mind of his victims.

Both drama revolve around a group of people that come together and take revenge on those that wronged them and others.

Both dramas deal around the romance story between a girl and a guy where the guy is not seen as ideal for her. Both dramas are very ascetic and have wonderful background music. Both have a lot of romantic couple moments. Generally they give of the same vibe. The only difference is that there is no age gap between the couples and while in "forbidden flower" the female lead is uprising the male lead, in "one spring night" it is the male lead that is pursuing the female lead

Both dramas deal around a rich girl that meets a poor guy.
In both dramas the girls fall for these guys and pursue them.
In both dramas one of the characters loves to draw.
Both dramas have a similar feel to them and
in both dramas one of the characters has an illness.

Both are crime dramas that follow a group of character over many years. In both dramas there is a protagonist that sacrifices nearly his whole life for justice. In both dramas there is the theme of corruption and the fight against it.

Both dramas are about female leads that get brutally bullied by classmates. Both dramas are quite extreme in terms of portraying that bulling. And both girls take their revenge for what has happened to them in very extreme ways.

Both female leads are very similar in terms of character. They both are the leaders of their squad, they both try to find out what has happened, and are very strong and smart female leads. Also the cases resemble one another quite a lot and have as a theme revenge.

Both dramas have protagonists that start out as good people but go through many things and change for the worse. Both drams revolve around a murder and the revenge of the victims. Both are very well done crime thrillers.

Both dramas revolve around a crime and a small child that witnessed that crime. Both kid's father was convicted for that murder. Both kids grow up and become police officers that try to make up for what their parent did. Both fight for the right way in the police field. Both end up investigating cases that resemble the case of their fathers. Both find out that there is more to the case.

Both dramas are about a young couple where the female dies. Both males are accused of being the culprit. Both males go to unusual means to prove they are innocent and to fight for their justice.

Both dramas revolve around a love story that ended in tragedy. In both dramas there is a murder and that is somehow resembling a past case. Both dramas have male protagonists that are somehow involved in the case and try to find out the truth. Both are willing to go to very extreme ends in order to catch the right person. Additionally, both dramas portray how brutal and hard life can be.

Both dramas are about an adult that looks after a little girl. Both adults develop parent like feelings for the child and both dramas have as a theme finding family and making your family. Both are wonderful heart warming stories