I wouldn't blame anyone for being put off by the premise of Mysterious Girlfriend X. The idea almost invites revulsion - a boy and girl united by a spit-bond, where instead of kissing normally, the boy just slurps drool off her finger. When you think about it, the mechanics involved aren't truly any more or less moist than a traditional kiss, but there's just something inherently off-putting about focusing on drool specifically. It feels like a gimmick, and not one that invites further investigation.

Fortunately, as it turns out, the weirdness of that premise is very intentional. Mysterious Girlfriend X is predicated on two central ideas, ones that will likely be familiar to anyone who was once a teenager. The first is “the opposite gender is extremely mysterious,” as foretold in the manga's actual title. And the second is “all this sex stuff is actually kind of weird and gross.”

Adolescent intimacy is a strange and uncomfortable topic. Teenagers don't suddenly reach a certain age and realize how they should engage with their peers, or what the proper steps of a relationship should be. They muddle through, discovering new feelings and sorting out what each member of a relationship wants one step at a time. They act on urges they don't feel entirely comfortable with, and try their best with the knowledge they have and what they can gather from their friends. They don't get it right the first time.

Mysterious Girlfriend X is all about exploring that space, and it covers it with a power of observation and willingness to be legitimately strange that you rarely see in romance manga. The characters here don't stress over arbitrary love triangles or make bold declarations of undying feelings; they worry about holding hands, and wonder what their partner is feeling, and slowly navigate boundaries together. It's a refreshingly grounded take on one of manga's most well-worn dramatic battlefields.

The manga takes the relationship of Tsubaki and Urabe one step at a time, with each of their new firsts or points of contention generally being mediated by the spit-bond premise. That premise is well-chosen - like how Urabe's design constantly hides her eyes, emphasizing how difficult it is for Tsubaki to understand her emotions, the use of spit emphasizes the awkward physicality of adolescent romance. At times, the use of the premise can shift from the smartly metaphorical to the blandly supernatural (like when Urabe uses her spit to test the nature of her relationship with other characters), but most of the time, the spit works as an excellent stand-in for the general clammy, imperfectly romantic physical expression of romantic feelings.

The manga also finds other ways to express the weirdness of adolescent longing, with the occasional dream sequences being one of the clear highlights. Mysterious Girlfriend X's artwork is generally workmanly, high in detail and nicely shaded, with an appealing retro character design style and a tendency towards conservative shot framing and panel composition. But when Tsubaki's feelings express themselves through dreams, the manga opens up into wild, almost Hieronymous Bosch-esque dreamscapes, where Tsubaki's desires to get closer to Urabe are garnished with spiraling cityscapes and strange, inhuman figures. The dream sequences are simultaneously captivating and frightening, a great visual reflection of the ambiguous nature of adolescent feelings.

But outside of the strong use of metaphor and visual highlights, the manga also just nails some of the early relationship fundamentals that are often overlooked in romance. Navigating boundaries, and deciding on physical comfort levels together. Trying to reach a greater honesty even regarding the feelings you're not proud of. Exploring the ways that teenage girls' greater maturity can often make them overwhelm boys at that age, and also how girls have just as many hormonal urges as guys. There are many offhand truths in Mysterious Girlfriend X that make it feel a little more true to life than many romance manga.

It's not all good news, of course. As I mentioned before, whenever the drool premise shifts from being a metaphor to an actual magic power, the story becomes a lot less compelling. Leaning into that concept results in a few weaker chapters here, and on top of that, it takes quite some time for Urabe to start coming across as a full person. The manga's focus on Tsubaki's feelings and the visual emphasis on female bodies clearly places it more in a boy's perspective, and that's fine, but it'd be nice for the manga to give more preference to the equally compelling and quite distinct feelings of the female characters. That said, more information on Urabe's feelings would actually lessen Tsubaki's consistent sense of bewilderment at her actions, and capturing just how scary girls are to teenage boys is actually one of the manga's core strengths.

Overall, Mysterious Girlfriend X stands as a surprisingly thoughtful take on adolescent romance. The story moves slowly and is far from dramatic, but the manga's close focus on small conflicts of feelings makes it seem more true-to-life than many similar stories. The premise actually works to the story's benefit, and the dream sequences are a wonderful, if rare highlight. If you're on the fence because of the weirdness of the core idea, I'd certainly give it a shot.