After recounting its islands, Japan found it has 7,000 more than what is known.
According to the Geospatial Information Authority of Japan (GSI), the islands number had doubled to reach 14,125 from 6,852.
GSI used advanced technology cross-referenced with past aerial photos to conduct the recount.
The new number does not include any artificially reclaimed land.
It is worth noting that the islands surrounding Japan have been at the heart of several territorial disputes.
Japan lays claim to the southern Kuril islands, controlled by Russia, a dispute that dates to the end of World War II when Soviet troops seized them from Japan.
Japan also says it has a historical claim to the uninhabited Senkaku Islands in the East China Sea, which it currently administers, but China has repeatedly challenged that claim.
Meanwhile, Japan and South Korea remain locked in a more than 70-year dispute over the sovereignty of a group of islets known as Dokdo by Seoul and Takeshima by Tokyo in the Sea of Japan, which Korea calls the East Sea.