Congrats on your assignment!
1. Before you go, get some coaching from someone who has expertise in Japanese mindset and experience in working there. (if you need people i have 2 excellent folks). Understand embedded, cultural protocols (verbal language, body language, gender competencies; mindsets).
2. Get clear on what your preferences are (for decision making, pace of work, what you mean by accountability) and what you value and what you do NOT value (core values, blind spots, hot buttons) so that you are very conscious of your habitual "way of being" and can self-manage your preferences.
3. Speak with another expat who's working in the same organization -- mine his/her learning, experience.
4. Create an ally(s) who will give you support and needed feedback.
5. creating relationships of trust and authenticity will be the foundation of your results. it's all about relationships.
You've been chosen for the role because of what you will bring to it. Be clear on what that is, and who will be assessing your performance. Make sure your performance measurements will be appropriate for the culture, and not "super imposed" from our Western "get 'er done" mentality. Situational leadership would be the mantra.
have an amazing time on assignment.