Who is Japanese teacher at the labor camp from Lost Names: Scenes from a Korean Boyhood and what is their importance?

The Japanese teacher in charge of the play came to the house to get the boy for the play. He was in no condition to perform, so the teacher asked the boy's friend to stand in for him and the teacher would hold up cue cards for him to read the speech. Ironically, the venue changed to one where the teacher must stand up to hold cue cards, which would be obvious to the audience.