It was an all day group interview session with 10 or so other applicants. The day began with introducing your peers, listening to an informative presentation about ECC Japan, a short break then a paper grammar test. Following a break for lunch, we were then grouped into 2-3 people and were required to demonstrate a demo lesson. Responding to the feedback the recruiters provided in their teaching demo is crucial here. Like what the others have posted, being enthusiastic is key. They want to see voice control, confidence and your ability to think on your feet. (Which is important for teaching anyway) The day then concluded with a short, private interview.

It was an all-day interview with around 20 other people. First is a long info presentation about ECC (make sure to take notes and look engaged). Next is a grammar test (if you fail they ask you to leave). Then lunch. After that was a teaching demonstration (they give you an example and you have to try to follow it). If they don't like your demonstration they ask you to leave. Finally if you make it to the end you have a one-on-one interview with the recruiter(s).