Rakuten Software Developer interview questions

A small online coding challenge before any interviews; one hour timed, solving a math problem (calculate area of two, possibly overlapping rectangles) as effectively as possible. Results not shared to the interviewee, except as passing to the next round. Also had to take an English test (I chose TOEIC, some others would have been acceptable, too), passing the required level with flying colors. All interviews took place online, over Skype, as I was not living in Japan. Application was for a position in any unit, and had two interviews on the first round, one of which I passed. A short, half-hour interview with one or two technical managers of the unit, talking about background, skills and aspirations. The following three rounds were with managers higher up in the ladder, with an assignment to read and write short essays on a couple of the CEOs books inbetween.