Maui05 comments

Ichinensei and boonme, it's not ash, it's red cinder. Ash is what falls from the sky during an eruption.

I just did Fuji for the first time, the last weekend of August, and the toilets at the top were literally overflowing with waste because they're composting toilets so people are supposed to put toilet paper in a different bin, but nobody did. They also charge to use the toilets, starting at 50 yen at the 5th Station, up to 300 yen by 8th station, even for men to use the urinal (except for one that I found, maybe 6th).

If you climb at night, it is already chilly at 5th station but a long sleeve and shorts is fine for a while if you keep moving. At the top it's pretty damn cold so bring a jacket, pants, and even a space blanket for when you're stopping to eat (seriously, it's that cold at the top).

Also, even though we should have had almost two hours at the top, it was so crowded that the trail just stopped moving at about 3am. There is a way to get over to the downhill section which has the cinder (to the left while hiking uphill), highly recommended for those who want to make it a quick trip and not sleep at the top to wait for sunrise.

Well that's what I wish I'd known, hope that helps for anyone planning to go next year! (September shouldn't be anywhere as bad for crowds)