Yen Press' youth imprint JY's new foray into middle-grade light novels is an excellent idea in theory and still pretty good in practice, with just one interesting detail that may take some readers aback: middle-grade fiction in Japan appears to skew a little younger than middle-grade fiction in the West. Whether that's down to translation choices that put the vocabulary at more of a chapter-book level or simply a cultural difference in publishing isn't clear. Still, both initial offerings, Phantom Thief Red and Horror Collector, are a little more fourth-grade than sixth-grade. It isn't a bad thing, especially given the plots of both volumes, but if you're going into this expecting Rick Riordan or Adam Gidwitz, you're likely to be a little surprised.

Fortunately, the story is enough to interest the target audience and light novel fans in general. Phantom Thief Red is a classic mysterious thief story: as Red, Asuka steals from the wealthy and corrupt to return ill-gotten gains to their rightful owners. Like many phantom thieves before her, she leaves calling cards and relies on impressive gadgets to pull off her heists, and her physical skills are through the roof. And if her brainpower is that of an ordinary twelve-year-old, no problem! She's got her genius cousin Kei to plan her heists and escapades, just as his father Keiichiro did for Asuka's dad during their time as Red. It's a very appealing concept carried out with aplomb, sort of like a light novel version of Saint Tail or Magic Kaito.

Narrated in the first person by Asuka, the story begins with her approaching thirteenth birthday, spurring her father to reveal the truth about their family: that each Kouzuki, at age thirteen, takes up the mantle of a phantom thief. They've been doing it for generations, and the most recent duo created Phantom Thief Red, with Asuka's dad as the muscle and his brother as the brains. Now they're ready to hand the reins over to their kids, cousins Asuka and Kei, although they want the new pair to keep the Red name, which is unusual. To that end, Kei and his dad will move in with Asuka and her father so that the older generation can guide the newer and the cousins can become closer to carrying out their missions better.

Asuka is all in, at least with the mysterious thief bit. First of all, it makes much more sense of her father's approach to raising her. She's also an enthusiastic person in general, willing to throw herself into almost any activity. Unfortunately, This leads to the book's biggest flaw: Asuka is often portrayed as someone with more enthusiasm than sense. Presumably, this is intended to play her off Kei, who is reticent and seems to present a flat affection, and it does work towards that goal. But it also makes Asuka hard to take at times while risking Kei becoming a stereotypical genius character whose brilliance leaves him with limited social skills. It functions for what the novel is going for, but even middle-grade (or chapter book) level readers are likely to spot these writing shortcuts. Some readers (or the adults who purchase the book for them) may also look askance at Asuka and Kei sharing a room and the mild hints of future romance between them sprinkled around the end of the volume. I'd hardly call either thing a dealbreaker, but it's something to be aware of nonetheless.

The caper element of the novel, which forms the latter half of the book, is the most substantial part. Asuka and Kei's mission is to steal back a green diamond that an unscrupulous dealer has shadily acquired. A mission that gets an addition when Asuka learns that her best friend's grandmother's beloved turquoise ring has also recently been stolen. Asuka realizes she will be raiding the lair of the city's premier gem fence, and there's a good chance he'll also have the ring. She's determined to do good not only for the wealthy true owner of the diamond but also for an old woman who has always been kind to her. This beautifully shows us who Asuka is: she is invested in the Robin Hood nature of Red's work, not just wanting to steal back high-profile items or help strangers. If Asuka will be Red, she will help the people who matter to her, no matter what anyone else says about it. It puts her in the same realm as many magical girl phantom thieves, and that's very appealing. She may not have a transformation sequence, but she has the heart of Saint Tail or Jeanne.

Action sequences are written smoothly, with appropriate danger and tension. Asuka relies on Kei to navigate the building and tell her when to release her traps. That adds to the pressure since she's not entirely sure she trusts him. Her acrobatics are well described, making it easy to picture the action, and if the illustrations don't add anything new, they're still nice to look at and help to make younger readers feel less overwhelmed by the thought of reading a full novel. There are no cultural notes, which is fine for this series (Horror Collector was a different story), but the pronunciation parenthetical for Asuka's name does feel clunky.

Phantom Thief Red is, overall, off to a good start. It's a fun read with action, a solid emotional core, and a smooth pace. It skews towards the younger side of middle grade, but it's worth picking up if that's not an issue.