Started the process 3 months ago. There were three rounds of interviews, each with increasingly senior people. The interview questions were less focused on hard skills and more focused on cultural things like why Japan and why Rakuten. Also, read Mikitani's 3 books and wrote 2 essays, as requested. The job was for a business manager position in Tokyo (I am currently in the US working in the same field).
On the second interview, I was explicitly asked about my current salary. The interviewer didn't bat an eye when they reviewed my salary and confirmed that is what I currently make, and even asked if I wanted to make the same.
Later, I was offered the position and the offered salary was about 60% of what I currently make (including bonus). There was no relocation offered at all, and no assistance offered for getting started in Japan. I tried negotiating in terms of salary and relocation, even providing documentation of standard market rates for someone in my field with my experience, and they didn't budge.
The people I interviewed with were very nice and the job seemed like a good one, but there is no way they are going to attract people from the US (or any other developed nation) if they do not compete with the market rates in terms of salary and benefits. On top of that, if they offer zero relocation assistance, I'm very unclear on how they expect people to pay out of pocket to move their lives to Japan. The budgeting for this MIGHT depend on the department. Unless you are a new grad with no experience, living at home with parents, or have no other options in terms of work (while also having thousands of dollars to spend to move yourself while accepting of the fact you will make less money overall), I'm simply not sure how their recruitment process makes any sense.
The funny thing is, reading Mikitani's books makes you think that the company is very interested in hiring foreigners to become more global, and maybe they are interested in that. But they aren't going to make it work if they don't actually compete for the talent. Gotta put your money where your mouth is, folks!