Yup, it's a Japanese-only PS2 game based on the currently popular Naruto anime/manga. If you're not aware of Naruto, it's pretty much like Dragonball Z, except with better animation, actual reasons for fighting, and ninjas instead of aliens. It tells the story of a young boy in the Hidden Village of Konoha, cursed with being the living incarnation of a feared nine-tailed demon fox spirit. Simple enough eh?
The game itself is cool; it's one-on-one fighting featuring characters from the anime/manga. Not fighting like Street Fighter fighting mind you, but fighting in an interactive environment, with items to be picked up, things to be destroyed, support characters to be called upon, and mighty cinematic ougis do be performed. If you've ever seen the Powerstone game in the arcades, it's a bit similar, and this is how I imagine Super Smash Bros. Melee would be like. The graphics are okay; not the best cel-shading I've seen, but definitely good for the material. You're restricted to 2d movement, but each stage has two layers, and each layer has various ropes, balconies, trees or whatnot that act as platforms. Most of the moves are available to all characters: punches, kicks, button-mashing combos, launchers, knockdowns, jutsus, counters (using the "transform into a log" technique), shurikens, kunai, surprise attacks from your allies, etc. Each character has three levels of ougi moves; when you connect with an ougi move, the view shifts to a cutscene-style depiction of the character doing their ougi on the hapless opponent. The opponent isn't helpless however; both players are given a sequence of button commands to push. If the attacker does it right and finishes before the opponent, he gets to do more damage and proceeds to the next part of the ougi. Since the ougis deal a huge (usually decisive) amount of damage, the defender usually wanys to do finish his sequence faster to greatly lessen the damage.
The only problem with this game is the lack of characters: Six are available at the start (Naruto, Sakura, Sasuke, Kakashi, Shikamaru and Rock Lee), and six more can be unlocked (Neji, Hinata, Haku, Zabuza, Gaara and Orochimaru); most of the other characters appear in ougis, as support characters or simply as stage backgrounds (you can hit them when you see them on the screen!) There's a lot of other things to unlock though: BGMs, voices, pictures, action figures, songs, video clips of each ougi, etc.
I'd recommend it for anyone who's a fan of videogames and the Naruto series.