2-4 days
This is an epic adventure, its well detailed in LP’s Hiking in Japan so if you’re thinking about going make sure you got one of those. In October it is freezing cold, but the solitude can't be beat. I left from Nara at dawn, took a two hour bus ride from the Kintetsu station, the north end of the hike, and began hiking mid morning. We reached Omine temple in mid afternoon, continued on to a small hut to spend the night, and came back the next day.