English Title: Simple 2000 Series Vol.61: The OneechanbaraD3's Simple Series budget games had two breakout successes that eventually managed to transition into their own franchies proper. One was Sandlot's magnificent Earth Defense Force, and the other is, of course, Tamsoft's magnificently-shlocky Oneechanbara. This is the first release in the franchise, and while everything the series embodies is there (blood, zombies, girls in unrealistically-skimpy outfits) it's still quite rough around the edges.
Japanese Title: SIMPLE2000シリーズVol.61 THE お姉チャンバラ
Publisher: D3 Publisher
Released: Aug. 26, 2004
Product Codes: SLPM-62525 / JAN 4527823992665
Considering the development schedule these games must have had, it's actually pretty amazing that the gameplay itself is already pretty solid, even if technically and graphically this would barely pass muster as a PS2 launch title. That said, there isn't really anything you're missing by skipping straight to later entries.
Released in Europe as Zombie Zone.