It took a while for Gregory Mele to get around to watching The Witcher on Netflix. That’s because, as the founder of Chicago’s only full-time European martial arts school, he spends a lot of time hitting people with heavy metal objects.

Now that he’s finally made it to the end of season 1, Polygon asked the founder of the Chicago Swordplay Guild — an expert on medieval- and Renaissance-era close-quarters combat — to weigh in on Henry Cavill’s skill with the blade. Turns out that Superman did a pretty good job.

“It’s believable that he’s a fighter,” Mele told Polygon via email, before launching into a glorious dissection of some of The Witcher’s best fight scenes.

Netflix recently published a YouTube video in which Cavill discusses his time fighting as Geralt of Rivia. In the video, which has been viewed nearly 900,000 times, he talks about the different swords he used while filming the show, and how he needed them to be modified to suit his needs. To Mele, the results are impressive.

“Geralt (in the show) is armed with a fairly short longsword, a fantasy equivalent to a form of the sword that might have existed around 1400 A.D.,” Mele said, “two-handed hilt on a blade no longer, or not much longer, than a one-handed sword, creating a weapon that is suited to use in one or two hands, which means you can also use in on horseback, or, if you must, with a shield. I think the blade is still a touch short, but as fantasy swords go, it’s reasonably realistic.”

Also realistic is Cavill’s stagecraft — and, in fact, the work of the entire combat arts team on the program, according to Mele.

“The fight scenes are fast-paced, dynamic and Henry Cavill has proven in Superman, Immortals, Justice League, etc, that he has a lot of physicality and can handle fight choreography,” Mele said. “They have designed a ‘style’ for Geralt: powerful slashes, usually made after he parries (what is called a hanging parry), straight thrusts and then quick transitions to a reverse grip, often holding the sword by the forte (base of the blade), with his hand wrapped around the guard. From here, he uses thrusts and in close slashes. He usually moves from one grip to the other in conjunction with pirouettes.”

What was particularly interesting to Mele was how Cavill positions his hands. Two fight scenes in particular caught the attention of fans, and both happen in the very first episode. One sees Geralt go up against Renfri’s soldiers in the streets, while the second pits the Witcher against Renfri herself, as played by Emma Appleton (Traitors). In both, you can see Cavill using a reverse grip — that is, holding his hands with his thumbs pointing away from the blade.

It’s that grip, in part, that gives Mele pause. Even though it looks good on screen, that’s not necessarily how swords were used back in the day.

“There IS some documentation for using a longsword in a reverse grip,” Mele said. “More often this was done on horseback, where the sword was drawn when the lance broke and then just thrust into someone (and forgotten) like a giant dagger. But there are a few techniques where the longsword is actually used in a reverse grip — found primarily in 15th century German sources.”

Mele said that the historical reverse grip was used primarily as a transition to a strong parry or a thrust, not necessarily for stabbing someone in the mouth and cutting their head in half down the middle as if it were a ripe cantaloupe.

“Geralt periodically uses the sword in a reverse grip to slash rather than thrust, a technique that would be largely useless against the fairly heavy clothing of medieval Eastern Europe (or shown in the show),” Mele said. “Medieval swords are sharp, but not razor sharp, nor does holding the blade in such a fashion really use the leverage of a long blade properly to cut. So, I’m afraid that a central part of Geralt’s fighting style owes more to Ninja and Zatoichi movies from the 1980s than it does historical swordsmanship.”

Of course, Mele admits that it’s not a fight choreographer’s job to be historically accurate. But Polygon asked, and so he was polite enough to weigh in. Personally, he said he really enjoyed the program.

“Overall the fights are fast and furious with some basic elements of solid fencing, some showy, less likely ones, a decided over-reliance and misuse of the reverse grip and some out and out stupidity,” Mele concluded. “I suspect 15-year-old Greg would have loved it! 40-something Greg … I can appreciate what they are trying to do — make Geralt’s fighting unusual and dynamic — and at least the fights are fast-paced and competent. Which is more than I can be said for Game of Thrones, which, for as slick as its battle scenes could be, managed to produce some of the worst dueling scenes I think I have ever seen.”

If you’re interested in a more historical take on a duel like the one between Geralt and Renfri in The Witcher, check out Andorea Olomouc on YouTube. Mele says the Czech martial artists know a thing or two, and package it nicely for public consumption.