Is it rude to leave at 5:00 PM?

In many traditional companies, yes. Leaving before your manager or the most senior person can be perceived as lacking dedication to the group.

How do I address my boss?

Always use their surname followed by 'san' or their job title (e.g., Tanaka-bucho). Never address them by their first name unless explicitly invited to do so.

Navigating Japanese Workplace Etiquette as a Foreigner

To succeed in a Japanese office, prioritize hierarchy, non-verbal communication, and group harmony over individual assertiveness. Spend your first three months observing office rituals like tea service and greeting patterns before suggesting major process changes.

Master the business card (Meishi) exchange. Carry your cards in a dedicated case. Present yours with both hands, face up, oriented toward the recipient. Receive theirs with both hands, read it carefully, and place it on the table in front of you—never slide it into your pocket immediately.
Observe the 'Ringi' decision-making process. Decisions are rarely made in meetings. They are made through informal 'nemawashi' (back-channeling) where you talk to stakeholders individually to gain consensus before the formal proposal is submitted.
Adopt a service-first communication style. Avoid saying 'no' directly. Instead, use phrases like 'that is a bit difficult' or 'let me consult with my manager.' Silence is a tool, not a sign of disagreement; wait for your counterpart to finish their thought before responding.
Prioritize 'Ho-Ren-So'. Practice the core Japanese management cycle: Horenso (Houkoku - Report, Renraku - Inform, Soudan - Consult). Keep your manager updated on status constantly to prove you are a team player who avoids surprises.

Is it rude to leave at 5:00 PM?: In many traditional companies, yes. Leaving before your manager or the most senior person can be perceived as lacking dedication to the group.
How do I address my boss?: Always use their surname followed by 'san' or their job title (e.g., Tanaka-bucho). Never address them by their first name unless explicitly invited to do so.