What two areas makes up the rest of Japan's land mass?

The rest of Japan's land mass is primarily made up of mountainous regions and coastal plains. Approximately 73% of the country is covered by mountains, including notable ranges like the Japanese Alps and the Chugoku Mountains. The coastal plains, such as the Kanto Plain and the Nobi Plain, are more densely populated and developed, serving as major agricultural and urban areas. These geographical features significantly influence Japan's climate, culture, and economic activities.