The ocean to the east of Japan is the Pacific Ocean. This vast ocean is the largest of the Earth's oceans and significantly influences Japan's climate and weather patterns. It is known for its complex marine ecosystems and plays a crucial role in international shipping and fisheries. The Japan Trench, located off the northeast coast of Japan, is one of the deepest parts of the ocean and contributes to the region's geological activity, making Japan prone to earthquakes and volcanic eruptions.