The meeting ended at 3:30pm I took a taxi to the Shinjuku West Bus Terminal where my Japanese hiking partner (Dr. Nagata) and I exchanged our business suits for hiking gear. After stashing our computers and luggage in a locker we boarded the Fuji bus carrying water, food (onigiri rice balls), and the appropriate clothing we'd need to climb the 12,376 foot Mt. Fuji in rain, light snow, and freezing temperatures. I travel internationally with carry on baggage, so I had to be very minimalistic in choosing the hiking gear to bring.
Our plan was to do a "bullet climb" - from the trailhead of the Yoshida trail to the summit of Fuji without stopping to rest/sleep at the mountain huts along the way. The trail was uncrowded given the bad weather and cold summit of early July. The trailhead weather was in the high 40's F and raining. Hiking in warm wet weather in total body Gore-tex is always a clammy experience. In a few hours, we climbed to 10, 170 feet, the 8th station, without feeling any altitude effects. As an experiment, we carried a small pulse oximeter and found that at 10,000 feet our oxygen saturation was about 95 with a pulse rate in the 80's.
The trail from the 8th station to the summit becomes much steeper, with loose, wet, volcanic rock. At this point those hikers who brought running shoes have difficulty traversing the trail. It's also the point at which the temperature drops and altitude effects become noticeable. Our goal was a steady pace and we climbed to the 8.5th station, the 9th station, and finally the summit arriving at 2:30am to light snow, 10 mph winds and freezing temperatures. Since twilight and sunrise viewing would be best 3:30am-4:30am, we decided to sleep a bit on the platforms near the shrine at the summit. Hiking at freezing temperatures in a base layer and gore-tex is easy, but sleeping is challenging. We did have mid layers for warmth which we added as our bodies cooled down. While at rest our oxygen saturation varied from 88 to 92 with a pulse of about 100.
Between 4am-4:30am, the clouds parted and we saw the sunrise - the rising sun from the highest point in the land of the rising sun.
After sunrise we explored the crater of Mt. Fuji and then began our descent through the large Torii gate at the summit. We walked through thick cloud cover and pouring rain, arriving back at the trailhead by 8am. In retrospect, I had a 24 hour day that began and ended with a discussion of "clouds" in Japan.