To answer that, let’s first look at what these terms mean:
Sen (先) sei (生) literally translates as “one who has gone before” but figuratively (and practically), sensei means teacher. The term suggests that since someone already has travelled down the proverbial path, that person is well positioned to serve as a guide to those who follow. In Japan, the term “sensei” is sometimes used loosely1 to address anyone who is skilled in the development transmission of knowledge but its significance should not be watered down. The Chinese have a saying: “If you meet a teacher on the road, forget what you are doing and follow him.” This speaks to the importance Eastern culture places on expert pedagogues.
Shihan is an honorific title for expert, master, or senior martial arts instructors and is created using two Japanese characters: shi (師) meaning example or model and han (範) meaning master or exemplary practitioner. A shihan has command of the material and can apply that knowledge to innovate and lead. The term renshi speaks to the character of the person; ren (錬) means refined, trained, and polished and shi (士) refers to a man/woman, gentleman/lady, or samurai of high status. A shihan, renshi is therefore a polished, technical expert who displays good character and therefore serves as a role model – both in practice and in disposition.
most shihan also have expertise in other areas
Broadly speaking, a shihan’s mastery is seldom limited to one field – most shihan also have expertise in other areas such as music, arts & literature, sports, administration, academics, or other disciplines ending in -do, and are capable of developing strong, long-lasting relationships. A shihan is typically a very well-rounded person.
So, if a shihan is ipso facto a sensei we return to the original question: how should a shihan be addressed? The answer lies in the nature of the relationship between the teacher and the student. Both titles can be used superficially in accordance with given definitions or social protocol (I was told to call you this) but they can also be spoken with meaning. A student who truly feels that someone can be their teacher or mentor and pledges in their heart to become a dedicated disciple of that person finds more depth in the term sensei and in the term shihan and in the relationship they signify.
Ask yourself, then, is the person you are addressing a sensei or a shihan or are they your sensei or your shihan – and try to determine the depth of that relationship. You can then use the term that is most meaningful for you.
Note: at the Charles Fink Karate Dojo, the term shihan is used in formal instances such as opening and closing ceremonies but Charles prefers to be addressed as Sensei.
1 Similar to the term “Boss” in North America.