Both are short dramas with wuxia elements, a focus on female characters, and two female leads with intense chemistry.
Both are police procedurals with two female leads that initially get on each other's nerves, but move in together and become close over the course of the series. While Duet of Shadows is set in the Republican Era, Sharp Downpour appears to be set around 2010.
Both are contemporary-ish set police procedurals with two female leads that team up to solve cases (and are also looking into a cold case they have a connection to).
Both dramas are mystery series that have two female leads with subtexty chemistry. Both also start with one of the main characters being suspected of murder.
Both are Republican Era dramas with two female leads (who eventually move in together) and have plots involving mysteries. Sun Yi Han plays one of the main leads in both.
They're both mystery dramas directed by Li Yutong that feature two female leads (a detective and a medical examiner) with imho nice chemistry. The actress Li Yuan is also in both (as a main character in The Evidence Tells and as a guest character in Duet of Shadows).
Both are short dramas with Yang Fuyu in a main role and feature a ton of chemistry between the two female leads.
Both are thrillers set in 1930s Korea that include LGBTQ main characters and a lot of the plot happening in an isolated location. imho 'Phantom' is more of an action thriller, while 'The Handmaiden' is more of a psychological thriller.
Both series are police procedurals featuring two leads with contrasting personalities and wonderful (and imho subtexty) chemistry.
Both are Republican Era dramas (Couple of Mirrors' is set in the 1930s and 'The Message' is set in 1941) that feature two female leads with excellent chemistry.
These are my two favorite adaptations of the novel! 'The Message' is a thriller full of unreliable narrators while 'Phantom' is much more of an action movie, but both have excellent chemistry between their female leads and a satisfying story.

