Probably, most university teachers, Japanese and non-Japanese alike, don't want to teach large classes. Many people say that it's easier for them to teach students in small classes. I can understand their feelings very well.
As long as they are university teachers, however, they have to teach large classes from time to time. And one of the most important things in teaching large classes for the teachers is to try to instill or maintain learning motivation. Without student motivation, large classes won't be successful.
Helping students feel confident
Whenever I have to teach a large class, I always explain to my students why they have to study a foreign language (this explanation is inevitable since quite a few Japanese students have already lost interest in English by the time they come to the univeristy or their desire to learn a foreign language has already become very vague), my teaching goal (i.e. to produce students who won't be afraid of making mistakes and who don't hesitate to speak up in English and who pay respect to the target language and culture as well as their own language and culture), and my plan and procedure of the classwork.
Unless the class was intended for improving students' writing ability, I seldom correct their grammatical mistakes (honestly, since I'm not a "native" speaker, I still have difficulty checking up on their English). Rather, I always try to encourage them to speak up and praise them for speaking up. An advantage of being a Japanese English teacher is that I almost always can guess my students' Japanese English(ness) correctly. So, I can also be patient with them. Very often they speak amusing English, clearly influenced by their way of thinking. The following examples are among the many which I collected during class.
(J= Japanese English / E: English)
1-1. J: Mr. Hirota is wide-[broad-] faced./ J: Mr. Hirota has a wide [broad] face.
1-2. E: Mr. Hirota knows a lot of people./ J: Mr. Hirota has many contacts.
2-1. J: Our garden is as small as a cat's forehead.
2-2. E: Our garden is as small as a postage stamp.
3-1. J: My father narrowed his eyes as he saw my little sister singing.
3-2. E: My father beamed with delight as he saw my little sister singing.
4-1. J: I've heard that story so many times that I got calluses on my ears.
4-2. E: I've heard that story so many times that I'm sick and tired of hearing it.
5-1. J: My grandfather is soft-headed for his age.
5-2. E: My grandfather is pretty open-minded for someone his age.
6-1. J: My mother told me to boil the dirt from my friend's nails and drink it.
6-2. E: My mother told me to go to my friend and ask him how to learn.
7-1. J: He has hair on his heart.
7-2. E: He's a smart aleck.
8-1. J: I'm still chewing my father's shin.
8-2. E: I'm still dependent on my father./ I'm still living off my father. / I'm still sponging on my father.
As I wrote above, I'm a Japanese English teacher and it's an advantage for me to be able to guess what my students are talking about with their "Japanese English." Non-Japanese teachers or "native" English speakers who can't understand this sort of English will have to lose a good opportunity to encourage Japanese students to speak up. They will also have to miss an opportunity to tell them that foreigners will learn to speak by speaking it and that it's not necessary to speak English like a "native" speaker (the need is merely to communicate effectively).
Some years ago, I taught a large class of 121 students. Fortunately and happily, however, all the students evaluated my class (my university has introduced an evaluation system and asks students to assess their teacher's ability to teach). 97 students out of 121 (80.2%) gave me Point 5 (the highest point which means "very interesting class"), 23 students (19.0%) gave me Point 4 (the second highest point which means "interesting class") and only one student gave me Point 3 (so-so). As to easiness to follow, 96 out of 121 (79.3%) gave me Point 5 (very easy to follow), 24 (19.8%) Point 4 (easy to follow), 1 (0.8%) Point 3 (so-so). As to the instructor's preparation for class, 95 out of 121 (78.5%) gave me Point 5 (very well prapared), 22 (18.2%) Point 4 (well prepared) and 4 (3.3%) Point 3 (so-so). As to my "enthusiasm" and "confidence, " 114 out of 121 (94.2%) gave me Point 5 (very enthusiastic), and 7 (5.8%) Point 4 (enthusiastic). And as to their satisfaction, 94out of 121 (77.7%) gave me Point 5 (very satisfied), 22 (18.2%) Point 4 (satisfied), 5 (4.1%) Point 3 (so-so).As a result, I got 4.63 (average point) out of 5 (highest average point). I'm certain this is a very high score and a good result of evaluation and I think I should be very proud of it. I have an American colleague who has gotten a very close result to mine. He taught a large class fo 86 students (though not as large as mine). Most of his students evaluated that his course was very useful, that they were lucky to join it, and that he taught them how to change from "Japanese English " into "natural English." The American colleague understands spoken Japanese very well (an advantage for a foreigner who teaches in Japan), and he is always very friendly, helpful and cheerful; he's, however, very tough with his students when his students behave very badly in class and tells them firmly their do's and don'ts in class; that's the reason he's very much loved by his students.
Although there seems no royal road to successful teaching in Japanese large classes, one of the surest things is, as I mentioned above, instilling or maintaining students' learning motivation. Another sure thing is encouragement: always try to encourage your students to express their feelings without being afraid of making mistakes. Teachers should first of all be enthusiastic because enthusiasm is catching in class. Each class should be carried out with enough enthusiasm.