A friend recently asked me to teach some English classes for her while she took a semester off to have a baby. Of course, I was happy to help out.
I quickly noticed, however, that these junior high school students were not studying to be English speakers. They were studying to become English ventriloquists. I have never seen students like these, who can speak English without ever moving their mouths. It was clear there would be no aspirated p's or b's in this class. Perhaps I should bring in some puppets to sit on their laps.
In order to take on this job of teaching budding ventriloquists, I needed a health check. The school gave me a special form to take to the doctor's office to have him fill out. The health check costs money, which is probably where the phrase "a clean bill of health" comes from. This health check, called kenko shindan, differs from the ningen dokku, or human dock, which is a more extensive medical check that probably includes scraping the barnacles off you.