Senpai/Kōhai

The concepts of senpai ("senior" or "upperclassman"; also spelled "sempai"note ) and kōhai ("junior" or "underclassman"; also spelled kouhai) permeate Japanese society. In fiction, you see them used most often in school settings, but the system also applies after graduation, in the workplace. Older students (or workers with greater seniority) are known as senpai, and junior students/workers (or kōhai) are required to defer to them, and address them with the honorific -senpai and polite speech patterns. In return, the senpai is obligated to look out for, and protect, the kōhai. Think of the senpai as people who are fully integrated into their school or workplace, and the kōhai as the inexperienced ones who are just getting acquiesced with the environment — with the added "sir"ing — though as with many Japanese tropes there is no precise Western equivalent. In real life, this trope is part of Confucianism's influence on Sinospheric (including Japanese) cultures. Thanks to the popularity of Japanese media overseas beginning to rise in the 2000s, the term senpai and its nuances are well-known in international fandom culture — the phrase "notice me, senpai" is borderline memetic — and because of this, many translations simply leave it untranslated with the expectation that viewers are familiar with the term and won't need context. Interestingly, kōhai has not become as well-known as senpai, despite being the other half of the dynamic. As a result, you'll occasionally see strange constructs like "senpai and underclassman" in translated Japanese media. The senpai/kōhai relationship is a rather popular one within the Yaoi Genre and Yuri Genre, perhaps because it's a quick and easy way to establish familiarity and rapport; compare Lover and Beloved.