I put this on the maritoki subreddit but I feel I shouldn't let it stay there. Here's my basic kinosaki identity reading.
Kinosaki shouldn't be cis woman because the whole point of the series is the choice of happiness over strict 'traditional' family adherence that believes "blood is thicker than water" and that having children is the most important thing you can do to continue that bloodline.
Kinosaki could be seen as trans because a key theme of the series is that WHO YOU ARE AT BIRTH shouldn't determine your value as a person, and that being able to biologically have children shouldn't be the only definition for being a woman (i.e. all the marriage options are only considered good for their blood, biology or birth right).
Kinosaki could also be seen as trans because reading her as a trans woman makes sense; she only ever reveals that she's a 'man' to people she's not conning because she doesn't believe she can be seen as a woman unless she's 'fooling' someone. Despite this she still chooses to dress and act as a woman in non-swindling social situations, meaning she wants to be PERCEIVED as a woman, not to mention she has never once chosen to dress as a man even in a private setting (only example being something gero imagined in his own head). Additionally, she wishes she were Gero's actual bride (see the wedding photo chapter) but doesn't believe herself to be an option not just because she doesn't see herself as a 'real girl' but also because she cannot bear children.
TL;DR trans girl kinosaki subtext my beloved that is all.
You're right and you should say it!!!!
Reducing Kinosaki to a generic yaoi twink technically fulfills the narrative's most basic goal of anti-natalism, but IMO it also requires denying Kinosaki's own characterization in most of the text and ends up leaving a lot of the thematic depth sitting on the table? Like you say, I don't think you can ignore the fact that she literally never presents masc when given the option to under safe or casual circumstances.
It's tricky because like, I fully think that the author themself does not have a particularly informed understanding of transfemininity and so it ends up being one of many series in which it's a perpetual uphill battle to argue merely that a character could be a trans woman amidst those who will demand every compromise away from that outcome. Anything but perfect and explicit legibility will always be reflexively denied (it tends to happen even when it is explicit lol), but I don't think we can or should ignore the way that Kinosaki is very specifically transfeminized within the text. I think this is a case where even when the mangaka wrote a character they likely did not set out to write as explicitly transfem, they ultimately do not exist outside of the broader cultural context that inspired Kinosaki's creation in the first place, and the good faith (if uninformed understanding) towards queerness there resulted in a lot of strong transfem thematic resonance within the story, whether it was conscious or not.
Kinosaki represents a kind of womanhood that is ideal in all surface-level respects, but is nonetheless rendered unacceptable by cisheteronormativity because her womanhood--a trans femininity--inherently threatens the assumed-to-be-natural hierarchy of patriarchy. Her lack of reproductive capability means that she's subject to the same cruel rub as the rest of us: Unable to be a Madonna, the most that one can aspire to is to be a Whore. She could never be accepted by Gero's conservative family because of the ways she ""fails"" to fulfill the expectations of womanhood, and she denies the ever-growing romantic bond between herself and Gero because she implicitly believes that """failing""" renders her unworthy.
I'm reminded of that anecdote from Torey Peters in Infect Your Friends and Loved Ones:
I stood naked with my back to him, combing my hair and heard him murmur, “You’re so beautiful, I feel sick.” I looked at myself, then his reflection in the mirror and saw it was true. I was beautiful and it hurt him. I doubt he ever complimented his wife that way. His wife did not possess the kind of beauty that triggered a desire that made him disgusted with himself. My kind of beauty does not trace a path to stable relationships, a dining room set from Crate and Barrel, a Thanksgiving turkey with his folks. He had no conception of what to do with my beauty other than choke on it.
The result is that Kinosaki is desired--to the point where her livelihood is dependent on it--but only so long as that desire is inherently surface-level and temporary. She's turned the transient honeymoon period where she can be loved without stipulation before The Truth™ has to be revealed and the shoe drops into her grift. It's a tragic trans power fantasy where she gets to do the betraying before she's inevitably betrayed. All it costs her is never getting to experience emotional vulnerability or an authentic relationship where she could actually be seen in her entirety and loved anyway :))))
Kinosaki is a woman that people can only love the idea of, but never the reality. And the parallel character motivation connecting Kinosaki and Gero is ultimately a desire for an authentic relationship without pretense. The series has a (much appreciated) awareness of the power dynamics intrinsic to its premise and cares a lot about defanging the implicitly exploitative ground on which most of the love interest meet-cutes are initially established. The meeting between Gero and Kinosaki in chapter 1 is explicitly and obviously corrupt to the point of comedy--playing out with Kinosaki rejecting Gero's initial thoughtless proposition even under the assumption that doing so will result in her death. And the series manages to avoid this feeling like a half-hearted way of rewarding a male protagonist with the adoration of its female cast for doing the absolute minimum because it's actually meaningfully reflected in the protagonist's own actions and intent. In truth, Gero himself cares about authenticity more than anything and actively sabotages his own surface-level goal to ensure that's possible. He isn't actually interested in the cisheteronormative notion of having A Wife as a trophy, a conquest, a homemaker, a source of sexual gratification, or a mother to his children. Gero just wants to marry his best friend, and that's a desire which is explicitly at-odds with the mandate he's been given. The irony is that once the two develop an actual rapport with each other, it is Kinosaki who feels that Gero is the one person she can develop a genuine relationship with (even if she still denies the possibility of ever acting on it more than platonically) without pretense or ulterior motive, because she believes deep down that it takes a literal murderer-for-hire from the criminal underworld to be on "equal footing" with her--who wouldn't have the right to pass moral judgement on her.
Transfem!Kinosaki is real, not because I'm holding my breath for the author to come out and say it in no uncertain terms, but because she navigates the world of her story in the way that trans women do. She acts like one of us, she looks like one of us, and she makes dubious romance choices like one of us lol. I am more than willing to call this duck a duck.
All this being said, those who lack the vision to make the surface-level reading of the text--that Kinosaki is a trans woman--will unfortunately never be able to arrive at the advanced reading of the text--that Gero is a trans woman :V
Look I'm just saying Gero seems really insistent on being A Really Good Ally To Lesbians and loves women in a way that denigrates himself to put the women he meets on a pedestal with this sort of reverent envy while also having a complex about failing to live up to what's expected of him as a "man" and being constantly anxious about coming across as predatory or overstepping boundaries. Girl, if you ever want to try transitioning about it you probably already have a poison in the back of a storage closet that makes you grow F-cups. Gero x Kinosaki t4t real in my heart. Imagine the beautiful world where Marriage Toxin concludes with both of the Gero family children ending up as lesbians who gleefully end their twisted bloodline with both spite and love in their hearts in equal measure.
