There was a thread on a certain anime board where a reader asked for a comparison between this title and Air Master. The response was mass snobbery towards both, but since I liked Air Master I was happy at the possibility of something similar existing. It isn't though, at anything but the most superficial of levels.
In the three kingdoms period of feudal China a great many people spent a lot of time chopping each other up into sub-people size pieces. It also seems they don't know when to stop because, according to this anime, their present day re-incarnations are still at it. Of course, filtered through anime, it becomes the warring schools period of modern day Japan as various fighters repeat new versions of the ancient tragedies. And naturally enough many of these ancient warriors now have the physical form of improbably buxom high school girls.
We get to meet one of the newest additions, Hakufu, as she's cheerfully beating the crap out of high school students as a way to pass the time. She possesses great fighting skills, large breasts, and an almost scary lack of anything approaching intellect. She's not actually the strongest fighter however, and ends up getting beaten down in the first episode, but hidden within her is a frightening destiny... well, it would frighten her if she was clever enough to have read the history everyone else is working from.
Yuck... this is really not the sort of thing I'm personally into. But I can play the role of the critic well enough to try and explain why. And as befits the introduction I'll do this by explaining why Air Master and this differ so much. One sort of fighting anime, as exists in Air Master, is an internalized battle to grow stronger. Fights are tests, or obstacles, to be overcome as part of that process. There is not actually malice, or fatal intent, in the vast majority of the fights. Another sort of fighting anime, of which ikkitousen is one, focuses on the outcomes of violence. Being strong allows for control, domination and the ability to inflict pain and death on others. Fights are life or death conflicts, blows are meant to kill, and the weak are pawns or tools of the strong.
This second form is not without dramatic power, indeed it is much easier to construct intense scenes in this mode. Cruelty, violence, tragic deaths and real physical injuries (including blood splatter) are readily turned into potent imagery and events. All of it given gravity here by being referred back to classical, and no doubt incredibly bloody, wartime events. I have no doubt there are some people who feel this harder edge makes it superior to something like Air Master. However others would wonder whether making such direct appeals to the darker side of human nature is really something we need more of.
Another potent human motivator is sex, and that shows up here too. Not only does it have instances of rape (not explicitly depicted) which is another expression of power dominance, it also has lots of sexual references and astounding amounts of extremely aggressive fan service. Attempting to count the number of times the female characters (who get most of the screen time) have their uniforms torn to the very limits of what censorship will allow is a futile endeavor. Naturally even when uniforms remain intact there's no shortage of jiggle (especially from the main) and anatomically detailed panty shots. Once again it is a personal decision whether such fan service, generally exposed while the female in question is getting beaten up, is something you want out of your anime. It is sort of scary however to think that a group of anime professionals got together to plan this rather obvious appeal to such a specific segment of the market.
What it doesn't have is a great deal of subtlety in character or story. The reason being that because it revels so greatly in the actual conflicts (and arranging the next panty shot of course) it tends to get bored by mundane elements like "why" or "who". Hakufu is a good example of this, other than her odd enjoyment of getting beaten up, she doesn't really have much of a personality to speak of. The angle of using ancient events as the foundation for the story, while it adds gravity, also detracts. It means that the foundations of many of the personalities have been "pre-formed". Why is Toutaku (one of the bad-ass school bosses) the twisted psycho he is? Who knows, you have to either know the ancient legends or make it up yourself because it didn't even happen in this life, let alone the show.
I don't hate this anime, which is sort of worrying in some ways. But even if this was the sort of thing I was into I still think it's a relatively average title. The writing isn't that great, the events largely meaningless and many of the characters vapid (Although Mou-chan, the Rei Ayanami clone, does her best... but even she seems to just randomly change without much logic or reason that I can see). However if you really like violent fights, and fan service, then this might be exactly what you want.
Of course it would be easier to be interested in it if the fights had better animation. In practice it really cuts down on the number of actual "contact" frames in the animation. As a result motion is quite jumpy, generally just a couple of steps between moves which are then "frozen". There is none of the complex physical interaction that made Air Master so fun, and as the power levels get high there's even less with the old "energy blasts" making their re-appearance (although naturally these ones also disintegrate school uniforms). The dialog in the series is less than sparkling which means the voice actors don't really get much to work with, Hakufu herself is just way too loud and can become annoying. The music selection is odd... pop stuff in the opening (perhaps what counts as club music in Japan) and some very strange music playing in the background at times.