Japan is 55% larger than United Kingdom.
Area: 243,610 km2 World Factbook
Population: 63,742,977 (July 2014) World Factbook
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom or simply Britain, is a sovereign state located off the north-western coast of continental Europe. Wikipedia
Area: 377,915 km2 World Factbook
Population: 127,103,388 (July 2014) World Factbook
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south. Wikipedia