This is not my first brush with an art form related to incest – back when I was in high-school, Tabitha Suzuma’s novel titled Forbidden (the same as my review's) created a stir in Goodreads, Cassandra Clare's Dark Artifices features two characters (though not blood related) bound to be forever in a sibling like relationship with each other due to circumstances.
The most recent one is the currently airing Taiwanese drama, Unknown, based on the novel Da Ge by Priest.

I don't condone or encourage incest by any means, but I have to admit, I would be in the exact same predicament as the leading characters’ friends’, had something as such happened before me.
I view almost everything from an objective point of view or through the eyes of the characters, which might be why I did not find this as abhorrent as expected.
Plus, the immaculate performances by the leading and supporting cast was an added bonus.

The Plot:
The story opens with two supposedly newlyweds moving into a neighborhood for a fresh start. We soon learn the shocking truth: Akira and Keicchi are not husband and wife, but siblings by blood. And hence begins a flashback into the past, which step by step explains what finally leads them to this point.

My Thoughts: Typical Japanese style, this drama is simple with an excellent cast, and a slice-of-life calm ambience whose very power lies in the hands of the characters.
A common aspect that I've noticed in such dramas and novels hinting at sibling relationships going awry is the children being forced to grow up as adults way too soon.

From the get go, it's clear that Hirose Akira, the younger sister was the mother of the household – it's not that anyone assigned her to do it, but their neglectful and absent mother, combined with a distinct alienation of Akira from the family pictures speaks volumes.
She automatically accepts the role and takes care of her elder brother Keiichi. However, somewhere along the way, she begins to realize that she has reached a point where she just can't let him go.

The same goes for Keiichi, who is heavily dependent on his younger sibling to take care of him. I have to point out, Keiichi had no idea about Akira's feelings towards him and it's not until she confessed multiple times that it finally hit a nail across his head.

Another common theme revolving around characters growing up too soon seems to be this – they seek permanent safety, happiness and warmth from someone whom they know will never be able to abandon them rather than try out transient emotions. Both Akira and Keiichi had only each other to seek out during difficult times. They are burdened by insecurities and responsibilities. (I did feel that Akira was a bit too stringent, though.)

Their friends, particularly Takumi and Go-san, are two other characters who have a fair share of their own dilemmas. Impossible unrequited loves, dysfunctional families, growing up different… Saraba, Yoki Hi had quite a lot going on.

The Cast: Is the real reason why this drama is a success. Hirose Akira in particular, has one of the most emotionally draining performances I've seen in such a subdued drama and I applaud Yamashita Mizuki for taking on such a role. One minor flaw would've changed the entire vibe of the drama from real and raw to plain creepy.
I'm familiar with Suzuki Jin's work and he did a decent job here. Kato Konatsu and Ito Asahi, Takami and Go-san, were excellently portrayed for supporting characters.

The Music: Was not too memorable for me. It was rather mellow and blended in with the scenes, without overpowering it.

Many thanks to massterchef @Tumblr for the subtitles. It was a different experience from my previous watches as it directly dealt with a taboo and sensitive topic.
As for that part… I'm not one to judge, and will not do so in this case. But, Saraba Yoki Hi was indeed a pleasant watch for me.