Western-style katsudon is a name with which to refer to the non-standard katsudon such as sauce katsudon in regions where the 'tamagotoji katsudon' is most common and hence it is simply referred to as 'katsudon.'
「卵とじカツ丼」が一般的でありそれを単に「カツ丼」と呼ぶエリアで、ソースカツ丼などそれ以外のカツ丼をさすときの名称。