After what felt like forever, interview information was finally sent out around the end of January.
For those reading that might be unaware, the long paper/online application that is completed in the fall is screened at the Japanese Embassy in your home country. From there, they send out information to the nearest embassy or consulate to you and they inform you if you have been selected for an interview or not. Typically you only get about 2-4 weeks notice of the interview date and time, of which you have zero control over. Additionally, any costs of going to the interview and returning home are not covered by the programme.
The first year I applied I believe I was given about 15 days notice of my interview. This year I only had about 10 days to prepare. Luckily, while I don't live in my interviewing city, I have a good friend whose home I am always welcome at so I at least had a place to stay and it wasn't too costly for me. Still, there is a lot to do in preparation for your interview.
The interviews themselves are conducted by the Japanese consulate nearest to you and are done by a small panel. You check in at a desk, then head to your interview room. The panel usually consists of one ex-JET, one Japanese national of some sort, and one community member though this sometimes varies. My first panel was two ex-JETs and someone from the consulate (Japanese), and my second interview was an ex-JET (whom was actually half Japanese but raised in Canada), someone from the consulate (Japanese), and an instructor from one of the local universities. The interviews are usually scheduled for about 30 minutes, but some are shorter and some are longer depending on your responses and if everything is running on time or not.
What to wear:
This is a huge stressor to most applicants and was for me too. But, of all the tips and guidelines I've heard out there, the best one by far is not to go out and spend a fortune on a brand new suit. I bought a nice suit my first year applying, and ended up not getting accepted. It wasn't too costly though as I got it on sale, so it's not like it put me under or anything, but in all honesty I could have used that money for better things. The best thing is to just dress sharp - nice slacks or a skirt, a nice blouse, and a blazer if you have one. For guys, a nice suit is great if you have one, but just nice slacks and dress shirt with a tie works as well.
What to study:
'Study' is probably the wrong word, but there are things you should definitely look into and brush up on before your interview. My process was to write out every possible question I could think of and write my answers out to them. I didn't try to memorize my responses' but it worked great for brainstorming - this way, if I did get that question or one similar, it's not like I would be completely stumped. You should brush up on the aims of the programme. You should already be aware of this from the application, but make sure you really understand the aims and work those into any possible answers and responses you think of. There are dozens of other blog posts and resources out there about the interview so I'm not going to provide a list. In general my questions in both years of interviews were centered around my past experiences and how I could bring those into the programme, how I dealt with stress and adjustment, and what I would do in certain situations.
Additionally, many interviewers will ask you to present a demo lesson. Both of mine were pretty casual - they just asked me what type of activities I would bring to a class of __ age group on the topic of ____. However, I have heard of some interviewers being more strict about actually roleplaying the lesson full out.
Other things you should review are your application itself, as many questions will come from this, and Japanese if you indicated that you spoke it on your application. They are known to ask a few questions in Japanese based off the level you stated you were, and I was even given a simple reading exercise.
How to behave:
This one is tough because you want to show a high level of professionalism, but you also want to appear warm, friendly, and highly personable. The interviewers are looking for both "genki-ness" (energy, basically) as well as professionalism. You can be a super funny and personable person, but if you can't also be serious when it's called for then that isn't good. Same in the other direction - a stiff serious person isn't going to be well liked by the panel. The best tip is to be yourself, be happy and try to relax but don't get silly - introduce yourself to everyone on the panel and even those checking you in, and chat with other applicants. This is all of course just my personal opinion.
After the interview:
Relax. Please. I know it's hard, but seriously.
After both my interviews I had a day of hanging out with friends planned - we even had celebratory cupcakes. It really helped me not overthink my interviews too much, which I think helped my not panic and nit-pick them too much even further down the road. The waiting period to hear back after the interview seems even longer and harder than waiting after the paper applications so do everything you can to keep yourself distracted. The worst thing you can do is over think and think about every little thing you did or didn't do during the interview - it will seriously only stress you out. Just know you did your best, and enjoy the time until the results come out - things tend to get crazy really quick once you know if you've been shortlisted or not!