In Japan, senpai (先輩?) is an upperclassman or upperclasswoman, someone of a higher age, or senior and kōhai (後輩?) is a protégé or junior. The mentor system is found at all levels of education, and in sports clubs, businesses, and informal or social organizations. The relationship is an essential element of Japanese seniority-based status relationships, similar to the way that family and other relationships are decided based on age, in which even twins may be divided into elder and younger siblings. The senpai is roughly equivalent to the Western concept of a mentor, while kōhai is roughly equivalent to protégé, though they do not imply as strong a relationship as these words mean in the West. More simply, these may be translated as senior and junior, or as an elder compared with someone younger in the family, company, or organization; the terms are used more widely than a true mentor/protégé in the West and are applied to all members of one group that are senior (the senpai) to all the members of another group (the kōhai). There is usually no average separation in age between a senpai and his or her kōhai.