Gen Nakatani responded to questions about the UFO phenomena during a meeting last week.
The enormous four-storey high structure has been designed to protect the coast against tsunamis.
A Japanese construction company is planning to build underwater complexes that corkscrew in to the ocean.
A new study has warned that Japan's whole population may be at risk from a huge volcanic eruption.
Fans of the popular Gundam franchise are to build a fully working scale replica within five years.
The Miyakozuka tomb in the village of Asuka is now believed to have been built in a pyramid shape.
The unnamed man from Japan allegedly ties string to the insect and takes it out for regular walks.
More than two dozen students at a girls high school in Japan suddenly became unwell at the same time.
A 300 million-year-old shark has been named after its resemblance to the famous Japanese movie monster.
Scientists have been left baffled by the accelerated growth of a seed that had spent a year in space.
A rise in giant squid numbers along the Japanese coast has left fisherman feeling a bit nervous.
A series of strange tales and incidents have appeared in the wake of the devastating 2011 tsunami.
A recently uploaded video filmed in Japan shows a tourist being chased by hundreds of hungry bunnies.
The huge deep sea crustacean was kept at a Japanese aquarium and hadn't eaten for 1,869 days.
The electrodynamic tether will be used as a way to help reduce the large amount of space junk in orbit.
The paranormal themed tyre commercial is so terrifying that it comes with its own health warning.
A Japanese firm is aiming to build a huge 250-mile-wide belt of solar panels around the moon's equator.
The Japanese space agency is hoping to blast a hole in an asteroid to find out what it's made of.
Tamu Massif encompasses an area covering 120,000 square miles in the sea off the coast of Japan.
Japanese scientists have identified an extrasolar planet that could be a prime candidate for life.