A yakuwari can be a duty, a role, or a part to play. The first kanji can be read as “of use,” which is a concept used in service (for if you are of use to the Emperor, you serve him and his interests). The second kanji is emphatically read as divide, as if splitting a log in two. Consequently, if this is a part, it is a part created through the division of labor.
Yaku (役), The Suffix
When we speak of such-and-such yaku, we speak of such-and-such role. This can apply to the theater, but linguistically speaking, life is just one big stage. This terminology can apply to real life quite well.
Senpai Yaku (先輩役)
This is playing the role of the senpai, the senior comrade. (Kanji: “Ahead” and “comrade”) Put at its most simplest, this would be the senior detective paired with a junior detective.
In Tokyo dialect, the “n” is pronounced “m” (for “sempai,”) but this is an issue of dialect (and ease of saying the word really fast). It is never written with an “m” in actual Japanese. It’s one of the relatively few cases of nouns not being pronounced as they are written.
Broadly speaking, it is the role of the senpai to engage superiors and peers on behalf of the team (even if it is a two-man team). This requires adequate speaking and leadership skills to say what needs to be said, and remain polite while doing it. This means being able to convey a lot of information in high level Japanese, when required.
Yet, even in Japan, the Western archetype of the senpai who bends the rules (a little) exists. The room for maneuver may not be very wide, but that is precisely why someone who knows and understands the barriers and the walls to each side can navigate the labyrinth of Japanese bureaucracy to attempt to lead things to a positive outcome.
Put another way, this is knowing what is black and white, and what is a gray area where initiative (usually discouraged by the system) can be invaluable – if it is done properly.
Kouhai Yaku (後輩役)
This is the role of the kouhai (spoken with a trailing “o” and a nearly mute “u”). Kanji: Behind + comrade. So, this is the junior comrade.
In a police drama, this would be the young detective paired with the veteran. As in American dramas, this can mean the rookie is either in need of adult supervision, or is far too accustomed to black and white cases. In either case, a dose of “the real world” (from the senior detective’s point of view) is delivered.
Fundamentally, the kouhai is not expected to be on the same level. Also one should keep in mind that this is as much a linguistic issue as a “respect hierarchy” one; you need to know how to address others, and dividing into senpai and kouhai is a quick and dirty, and therefore useful, way of organizing social roles in a simple and uncomplicated way.
The thing I really like to remember is that the senpai is expected to actually take care of his kouhai (singular or plural). In other words, the kouhai getting the coffee is not the limit of the relationship; it isn’t just lip service. Peers will not respect a senpai who doesn’t look after his people.
Conversely, the kouhai is expected to support the senpai in any way possible. This is because, where teams are concerned, the whole is greater than the sum of its parts. Japanese society never sees things in terms of just the individual, because society’s too big to squish things down to that (unless you’re a Shogun or something).
Otori Yaku (囮役)
An otori (囮、おとり) is simply, in English, a decoy. The kanji suggests a cage and the kanji for “become”; therefore, the deceived one becomes trapped. Thus, the concept of a decoy: that which lures and ensnares the enemy.
In many video games, this is an unofficial role, but in some, you can deliberately set someone to be a decoy and draw enemy fire from other members of a team in the field. The latter occurs in “Super Robot Wars: Scramble Commander”, a game I have played. Drawing off fire allows other units to attack uninhibited or charge up a special attack.
Thus, using a particular command from the battle tactics menu, under “Support,” allowed the player to assign someone to decoy duty. This is a temporary role, and decoy duty can be changed.
I use this to demonstrate that not all roles are permanent, but they are roles nonetheless.
Division of Labor
No one can be all things to all people. Japanese society thrives on this principle, and always has.
This is not to say that all of Japanese society was always based on castes. For instance, samurai were only made a permanent hereditary class at the end of the Sengoku Jidai (戦国時代), or Warring States Period, to end the upward mobility offered by chaos and strife (and therefore dampen the chaos and strife). Also, as shown in Seven Samurai, a samurai could cut off his top knot and shave his head and become a monk.
Put another way, if you couldn’t go up, you could go down.
Even so, many social roles are very long-term in nature. More to the point, Japanese society is comfortable with roles and collectively wants people to play them. This is an issue often decried by left-wing activists (as they would in any society with strong roles not defined by political value), but whether simply a matter of cultural sympathies or a strong, rarely changing societal mandate, the idea of roles is a big one to keep mental track of when dealing with Japanese culture.
Roles are not absolute, but they are important.