Katanagatari is Nisoisin's take on chanbara (or sword-fighting) stories, and contains much of what he's known for: tons of dialogue, even more puns, brutal fight scenes, creative skewering of cliches, and a cast of characters who initially appear to be Frankenstein monsters of anime cliches and archetypes, until they turn out to be anything but. Its twelve episodes (each about forty-five minutes long) released over twelve months effectively parallel the adventures of the show's protagonists—Togame, a stragegian, and Shichika, a swordsman who doesn't use swords—and their search for twelve "Deviant Blades" over the same amount of time.
Nisoisin clearly breathes pop culture, so if you went into the show looking for another light-hearted, remarkably meta genre exercise, you wouldn't be far off. Katanagatari takes great pleasure in exploding expectations, from the way the fight against Hakuto Hari in the fourth episode plays out, to how the Deviant Blades effectively evolve as the series continue from an unbreakable sword to a "sword" that renders all other swords obsolete. But if you're expecting another Bakemonogatari, think again. For one thing, cult director Akiyuki Shinbo didn't even touch this show, so while the visuals are actually pretty great (courtesy of studio White Fox, who later produced Steins;Gate) they don't quite measure up to Shinbo's inspired insanity, especially in the show's first few episodes.
The other thing is that Katanagatari is one of the most brutal shows I've seen in ages. None of the protagonists are what you'd call conventionally heroic. The formulaic sword-hunt that forms the show's spine goes in a very different direction than expected. People die, by the truckload. Soldiers, civilians, women, children, people you've come to love, even despite yourself—no-one is safe. What starts as a dance with chanbara tropes becomes genuinely bleak and frightening by the end, tearing the very premise of the show itself into pieces.
It doesn't quite have the face-value sparkle that Bakemonogatari does, and may very well be condemned by history as the inferior work. That would be a mistake. Katanagatari is slow-paced, scrappy and sometimes even infuriating. But it is special, in that strange undefinable way that very few shows are. A masterpiece it might not be, but as a cult classic it deserves to be seen.