As a Japanese passport holder, you'll be pleased to know that your travels to Norway are visa-free for stays of up to 90 days, allowing ample time to experience the stunning fjords and vibrant cities like Oslo. You can choose between a tourist visa for exploration or a work visa if you plan to stay longer for employment, though for short trips, no visa is required at all. Considering Norway's crisp air and natural beauty, planning your trip outside the peak summer months of June to August might offer a more serene experience and potentially lower flight costs from major hubs like Tokyo. While English is widely spoken, learning a few basic Norwegian phrases like "Takk" (thank you) will certainly enhance your interactions with locals as you explore this beautiful Nordic nation.