Ten of millions of years ago, when the archipelago of Japan was separated from continent, Fossa Magna was formed. After that, Mikasa Sanchi was formed. Hundred of thousands of years ago, Komitake was formed by volcanic eruption. Tens of thousands of years ago Kofuji volcano eruption covered the Komitake volcano. Over 10,000 years ago, Shinfuji volcano was active for a long time, and erupted several times to create modern day Mt. Fuji. The most recent record of eruption is that of Hoei Zan in 1707.
In Yamanashi prefecture lies Oshino Ninja Village (Oshino Shinobi-no-sato), a place where you can experience all things ninja.