A lot of the comments I've seen in response to this manga seem to be from reading this oneshot as a piece of light-reading; while that's not a bad thing, I found "S no Kaikoroku" to be an insightful and serious look at BDSM and its modern perception. That said, I only consciously noticed after I approached it as a piece of literature, having previously read some of what Ogura is criticising. "S no Kaikoroku" is distinct both in the context of most manga representations of BDSM (especially shoujo) and the author's other works (which tend to be light-hearted and, in longer works, have a serious element of varying weight).
    Several things to point out: 1. From the first page, the protagonist addresses the problem of popular perception of SM as an unanswered, serious, and underestimated question. 2. All the text boxes are either black or black gradient: this is characteristic of horror manga and is otherwise generally used for emphasis of negative things; Ogura has used the contrast of the light background with the impact of the black text boxes. (Her use of black and white through out the whole work ties in perfectly to the oneshot's prominent extended metaphor.) 3. Unlike typical representations of SM type relationships or typical semi-role-reversals, here the masochist isn't some passive innocent lured unsuspectingly into a trap laid by a manipulative sadist nor is BDSM primarily humiliation or dominance (rejecting the whole "BDSM is extreme teasing" or "a simple fetish" views). 4. Ogura also plays on expected eye-candy (especially what is typical of shoujo) by making all of the "eye-candy" and acts of lovers, most notably kissing, distinctly abnormal. 5. The focus, as suggested by the title, is the sadist's psychology (vividly portrayed), which is both unusual and allows the issue to be addressed without victimization or criminalization of either side of the relationship. (Side note: clearly Ogura did her research.) 6. While the masochist's wounds are noted, no one suspects anything (note the protagonist's friend and the other girl): people see what they want to see and avert their attention from something they would rather not see. 7. The protagonist, from beginning to end, shows a distinct discomfort with his position and a certain degree of skepticism (note the first and last three pages) yet remains in love. 8. There is a complete absence of any adults or authority figures. 9. The story is mostly an extended flashback encased in an epilogue: this is necessary to comprehend the work.
    As for most of the complaints regarding this oneshot, while I have no intention of disregarding them, I cannot think of any way for the author to have successfully made her point otherwise. It is because Ogura wishes to problematize the present outlook on BDSM that the manga had to progress the way it did. Including the masochist's psychology would change the focus of the work (she needed to focus on one or the other, not both). The lack of ascribing blame the factor that allows Ogura to address BDSM as an issue. The brevity assists allows Ogura's point to be clear without victimizing either side, and the rather physical extended metaphor is essential to that end.
    Although it is marked "Mature," Ogura has carefully avoided the work being "Adult," and honestly, while it's hard to tell who would enjoy this work, I think they should be above the mental age of fifteen or so. As a whole, the account is vivid and thoughtful. It is neither too much nor too little detail, and the reader can clearly see the development of the protagonist's emotions and how various forms of inflicting pain came to be connected to his expression of love. It is impossible to say which one of the characters is more at fault, whether abusive or excessive, but the total absence of adults and authority seems to stand out. The end result is extremely complex and thought-provoking. In fact, the whole story is essentially a question.

... Last updated on April 25th, 2021, 4:40pm

this is a story of discovery, story of change. the art is bit too shoujo ish to convey passion, but it have lots of potential. for hot S&M read nana to kaoru, but this manga is more on the psychological side. i would love a longer story on these two, and the girl's side how she discover her self.

I personally didn't get the S&M feelings. however, the story could have been longer and delved deeper into the psychological side of things. Maybe then i could have understood what Natsukawa felt.

although i'm happy for their happiness with each other, but it's so twisted, it is too much

I don't understand this S and M stuff very well. I know what it is, but WHY WOULD YOU WANT TO HURT THE ONE YOU LOVE AND BE HURT BY THEM?!?!

I gave it a 4 for the art and a few of the story pieces...it wasn't for me.