The route of "Sainokuni Classic Challenge" was originally produced by Coedo-Ooedo Trianic World, as their first 100 mile trail running race, which 51 runners challenged.
And nobody could cross the finish line in Sep. 2016.
The result was so shocking that some crazy runners treat the route as a kind of legend.
From 2017, the producer became some more clever, changed the route a little easier, extended the cut off time 2 hours longer.
It makes their race not impossible game, so nowadays less than 20% runners can cross the finish line in time every year.
And now, the first impossible route is not used by general runners, but the attractive challenge of "100 mile that nobody has completed" still remains.
Some crazy runners continue their personal challenges every summer.
Their ultimate goal is to beat the time limit of the first race, 33 hours.
It would be FKT of this route, of course.
The route consists of one loop of the north stage and two loops of the south stage, for a total of three loops.
The start and goal of each loop are New Sunpia Saitama Ogose.
The loops are called "stage", but of course it runs continuously, not stage race.
Although it is basically a series of low mountains, there are some exceptional panorama-view points.
Mt. Doudairayama in the north stage and Kan-hasshu Miharashidai in the south stage.
The view from these peaks are wonderful.
And it is also a route that goes around a historic temple and shrine.
There are Jikoji Temple on the north stage, Takayama Fudoson, Neno Gongen, and Takedera on the south stage, for example.
You can feel that the ancient people have passed these trails.