I submit the following as an opening bid: a mountain as iconic as Fuji-san deserves an FKT, I am certain someone has done much better without documenting their effort. Speaking to a Japanese mountain guide, who claimed to work the mountain everyday, mine was fastest he had seen, but he had heard of a “local boy” that made it to the top in less than 3 hours, more than an hour faster than me. The “local boy” obviously would have been able to climb up, do a loop of the summit, stop for a 3 course meal, and still make it down with time to clean up and greet me at the bottom.
This was my first time up Fuji and I chose the Gotemba Trail because it was the longest, had most elevation gain and was the least popular. By all accounts, many of the other trails can be so crowded that you are literally standing in line for the person in front of you to move one step—not the way I wanted to go up Fuji. I started at the Gotemba New 5th Station at the Torii Gate at 8:44 am 6 August 2014, made it to the Gotemba Trail summit in 4:02:45, did a loop of the summit in 32:47, there are separate ascending and descending trails, the descent (down the Great Sand Run) was in 1:09:47. For a total time back at the Torii Gate of 5:45:22. I did it self-supported, in that I bought water at the 7th Station. My ascent and descent numbers are a little off, I recalibrate my GPS on the ascent at the 3000m sign, I think the descent number is accurate the ascent should match. Below is my GPS data, a map for those interested in my route, and a few photos: at the start, a bad selfie at the 7th Station, a bad selfie at top, and finally finished at the bottom.
Gotemba Trail Map: fujisan.rash.jp/pdf/Gotemba_Trail_E.pdf