OneChanbara (お姉チャンバラ), initially defined The OneeChanbara , 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 and chanbara . 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.