Basically, the BSS genre is considered a sub-genre of ntr , but in Korea, there is a fairly constant movement to strictly distinguish BSS from NTR. In Korean creative works such as dramas, web novels, fan fiction, and fan comics, when it comes to NTR, in most cases, a relationship of at least a romantic relationship or flirtation is required. If the relationship is set to nothing, NTR fundamentalists will storm in and say , "It's just a male (female) owner's delusion. Where on earth do you think it's NTR?" It is bound to receive criticism. To take an extreme example, a homeless male protagonist falls in love with a high school girl one day and says kind words to her, and follows her around. Even the situation where he sees the high school girl dating a male high school student from the same school becomes NTR. The reason why the term BSS, which was buried without much response in Japan, is particularly popular in Korea is because a term was needed to refer to the intrusion of a third party between a man and a woman who are not in a relationship in order to avoid such tackle.