It's still Soul Edge in every version in Japan. Apparently non-Japanese gamers were believed too thick to know that an "Edge" can be the blade of a sword (I can't remember where I read that). The stupid part is that the game was called Soul Edge because that was the name of an important sword in the game's storyline (as was Soul Calibur) - despite the name change, the sword itself remained to be called "Soul Edge". So really caling the game Soul Blade makes less sense the more I think about it...