What are Senpai and Kohai really? 先輩と後輩とは？
I often receive the questions that are pertaining to these two popular terms. I realized that those questions came because the western people do not know the real meaning and the rules that are attached to them.
These words are very popular in the dojo but you are puzzled and wonder what they really mean. The confusion or misunderstanding arises because the concept behind these two terms is tied closely to the unique Japanese cultural concept or behavior. Let me explain this unique cultural concept so that you will have a better understanding of what is behind those two words.
First, let’s look at the kanji and their meaning so that you will understand the construction or foundation of the terms. Kanji for Senpai is 先輩 and Kohai is 後輩. Sen or 先means early, in advance, first or prior. You are familiar with this character as it is used in other karate words such as Sensei and Sen no sen. Hai, 輩 means fellow, person, colleague, or people. So, Senpai means a student or a practitioner who started training karate earlier.
Ko, 後means later, afterwards, rear or aback. So you can easily guess that the meaning of Kohai is someone who started later than another or other practitioners. It is a comparison normally between the practitioners typically in the same dojo but it can expand to a larger organization or to an entire ryu-ha (style such as Shotokan).
This is a very straight forward and simple concept. Therefore, there is little confusion about this concept among Japanese. Let me give you an example. If you started your training at your dojo, say, in January 2000 then you are a Senpai to all the students who started later than February 2000. You are a Kohai to all the practitioners who started training earlier than your starting date. Some Japanese are very precise and detailed minded so that a shorter timing difference than a month makes the separation. Even one day difference may determine him to be senpai or kohai. If a person joins on the same day or very similar timing, he is called Dohai 同輩. Do (同) means same or equal. The sound of do is used in other characters so do not get this mixed up with another popular do (道) which means way or path as used in Karate-do.
In Japan, the concept of seniority is highly important and the division or classification is exercised or enforced. For instance, there is a definite hierarchy among the siblings according to their ages. The eldest brother or sister has the most power or respect compared to other siblings. Of course it comes with more responsibilities too. This goes to every aspect of Japanese society in different degrees. Two obvious places are dojo and school. It also applies to the workers as life time employment was once very common in Japan. Even though this custom is fading away in the Japanese companies the legacy of calling Senpai and Kohai in an company is still very common.
In the western world there is no strict hierarchy that is tied to the time. For instance, a male sibling is simply called a brother. To show he is older you have to add elder in front of brother. In Japanese we have one character, 兄 to describe that. Secondly, the western people are more mobile and do not stay in the same dojo for many years.
In your dojo I assume Senpai is understood as a senior student or even an assistant instructor who is not a qualified or main sensei. In some dojo all the black belts are called Senpai and the brown belts and the lower ranks are called Kohai. I understand why this is happening
Let me share one interesting thing that can happen in Japan with Senpai and Kohai. Suppose you are shodan and so is your senpai who joined the dojo, say, one year earlier. He would become eligible to take a nidan exam sooner than you. But suppose he got sick or quit karate training for a few years. You can go ahead and advance to nidan while your senpai will remain as shodan. If your senpai comes back to the dojo then you will sit in the senior position. This sitting arrangement is same in Japan but what is different is that he remains as your senpai as when he originally started karate does not change. This could cause some confusion even in Japan so in a Japanese dojo one typically cannot take a next exam until all your senpai take their exam first. This happens typically in the high school and university karate clubs. All the senior students become shodan or advance to nidan, etc at the same time.
I know this concept will not work in the western world and cannot be exercised. On the other hand, I think it is good for the senior practitioners to know about this cultural concept in Japan that when you started karate is the deciding factor in determining senpai and kohai. By knowing this, you will be able to answer to a small puzzle why Okazaki sits in front of Kanazawa even though he got his 10th dan later than Kanazawa.