OneChanbara (お姉チャンバラ), initially defined The OneeChanbara (THE お姉チャンバラ), is a series of action-adventure hack and slash video games originally developed by Tamsoft for D3 Publisher's Simple 2000 series. The title is a portmanteau of the Japanese words onee-chan (お姉ちゃん, lit. "big sister", but also a colloquialism for a young adult woman) and chanbara (チャンバラ, "sword fighting"). The series centers around Aya, a cowgirl who wears a scarf and wields a katana, who is pitted against hordes of zombies and other monsters.