Are you planning to climb alone? During summer Mt. Fuji can get very busy, often long line of people forming heading to the top. Mt. Fuji does not have river running from top of the mountain, have to carry your own drinking water. But because of the added weight, pretty much most climbers opt to buy water at rest houses along the way up.
I was told that it is rare to have a mountain higher than 3000 m elevation which can be climbed without having high elevation climbing experience, where Mt. Fuji is one of few in the world. I was told that if you have experience in high elevation mountain climbing then climbing Mt. Fuji alone should not be a problem.
Kitaguchihongu Fuji Sengakuji is located 850 m elevation. The peak of Mt. Fuji, Kengamine, is 3776 m elevation, where the shrine located at the top of Mt. Fuji, Kusushi Jinja, where most climbers aim as a destination is at 3715 m elevation, which is not the highest point of Japan. Kengamine is another 50 – 60 min. walk around the top rim of Mt. Fuji from Kusushi Jinja. Kengamine is located at another side of the rim from Kusushi Jinja. LIkley you will be attempting 2865 m climb.
Local tourist department has a record that a man climbed up (not down) Mt. Fuji from Kitaguchihongu Fuji Sengakuji to Kusushi Jinja in 2 hours and 30 min., which is considered to be the fastest record of climbing up Mt. Fuji. Enjoy Mt. Fuji.