This social structure is extremely rigid, and begat the very formalized 先輩 (senpai, senior) and 後輩 (kouhai, junior) relationships. Senpai-kouhai relationships can perhaps be seen best in sports. In high school baseball teams, for instance, the 1st-year students must do everything for the 3rd-year students, including getting them drinks and snacks, cleaning up after games or practice, and washing uniforms. This is done regardless of baseball ability. When the 1st years themselves become 3rd years, they of course expect the same thing of the new 1st years. This relationship is perhaps not so rare, as it is also seen in British public schools, among other places. However, in Japan this relationship will continue as long as the two people know each other. Even long after high school graduation, the former 1st year will always be considered kouhai by his senior/senpai. And he will defer to his senpai accordingly, often even calling the person “Senpai” in daily life.
These relationships don’t have to have been close to be formed. If two people meet for the first time, then find out that they went to the same university, the one who graduated first will automatically assume the role of senpai, and expect deference from the other person. For example, if a senpai asks a kouhai to lend him money, it’s hard for the kouhai to refuse.
This formalized senpai-kouhai relationship can be abused, of course. One of our favorite TV shows is 行列のできる法律相談室 (Gyouretsu no dekiru houritsu soudan shitsu, loosely translatable as Wildly Popular Legal Advice Office), with the acid-tongued Shinsuke Shimada (島田紳助) as its host. 行列 (gyouretsu) is a line, in this case symbolizing a line of people waiting outside the door. の出来る means “can have/do”. Anyway, a recent segment on the show featured a question from a correspondent about senpai/kouhai relationships. When a new guy joined his workplace, he asked how old the new guy was. Finding out that the new guy was older than him, he was put into the kouhai role, so had to do whatever the new guy asked of him, including covering his shifts, cleaning up for him, and so on. After a few months of this, he happened to see the new guy’s driver’s license, and noticed that the new guy had lied about his birthday, he was actually younger than the correspondent, and so shouldn’t have treated the correspondent as kouhai! The correspondent wanted to know if he could sue the new guy for damages for the extra work he did while thinking the new guy was his senpai. (The answer, unfortunately, was that he’d be unlikely to win, as everything he did was at work, and he was still getting paid…)
The most common difficulty, of course, comes when someone is simultaneously both above and below you in social standing. For example, if you are new to a company but older than the person who is training you, who is the real senpai, and who the kouhai? In this case, the relationship would most likely change depending on the situation – when they are at work, the new guy would be kouhai, but if they went out for drinks afterwards, he would act as senpai, because of his age.
Also, note that these junior/senior relationships only really function for people who are somewhat close in age, usually within 10 years or less of each other. For people who are further apart in age, the relationship is simply one of respect for elders.
It’s often quite difficult for foreigners in Japan to remember to maintain these formal relationships after getting a little close to someone. When you start to get friendly with a person, you may naturally feel that you have become equals in the relationship. However, remember that no matter how close you get, relative social standing will always play some part in your relationship. If you remember to call your seniors “Senpai” every once in a while, you might find things going a lot more smoothly!