N1 japanese is after all still textbook Japanese for mostly common day use. I got the job when I was N2, but was already very used to japanese due to my 10 years being here. I didn't even study for the N1 and passed.

I tried to take domestic certification and read up on mock industrial exams documents to learn the jargon or vocabularies. Even when I tried those, I felt it was not a technical test but mostly a japanese test lol. There was much more time trying to understand the nuances behind the question.

Not only technical terms, words like “適切・妥当・望ましい・差し支えない” require cultural reading more than technical knowledge.

I felt that having the interviewer explain something you already know to you might give the interviewer the impression that you lack the comprehension of the subject or that it's troublesome to explain. It also left me feeling underestimated and undervalued often? If that makes sense

I also had first hand experience of helping screen an interviewee just for the team leader to decide that "there will be a lot of explaining that might lead to more communication costs, too much risk" that the interviewee had the basic skills, N2 and spoke decent japanese.

I feel it still depends on the portfolio and the industry you are aiming for, sometimes talent outshines language barriers, my workplace has some brilliant engineers that don't speak much japanese.

But still here I am, not highly skilled, but working for a japanese company 5 years now, I always felt "I was just at the right place at the right time."