I bought a used copy of Bleach DS. Resetting the data is not a trivial task, as none of the menus are in English (of course).
To delete the Bleach DS data, there are no button combination at the startup screen, but rather you must go into the menus.
SCREEN 1: On the menu screen choose option (second from the bottom).
SCREEN 2: On the option screen select the third option from the top.
SCREEN 3: Select the last option, Save data.
SCREEN 4: It will show four options: Game Data, Record Data, Wi-Fi Data, and All data. Select any one of them and it will then give you a (yes/no) prompt if you want to delete the data.
Thanks to Carlson at Mad-Gear for help on this.
