Japan is 253,766 times larger than Mesa, Arizona.
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
Area: 1 km2 calculated
Mesa is a city in Maricopa County, in the State of Arizona and is a suburb located about 20 miles east of Phoenix. Mesa is the central city of the East Valley section of the Phoenix Metropolitan Area. Wikipedia