The oldest and most developed bike park in Japan... pretty difficult to get any information on the place as well, unless you get an email from an awesome local rider (thanks Danni!)
There are 15 different lines that intersect with each other and you can combine them in many ways to have the ride of your choice.
The old A-course starts with a black diamond numbered 11 right now. It's some very technical tight single track with a few decent drops built in. It leads into #7 which is a blue course that is extremely fast, fun and has some good jumps/drops built in. From there you take either #8 which is the same flow flavor, or you can take #14 another black diamond which is more rooty, twisty droppy tight single track.
The "B-course" starts with blue #6 and it is slow, tight, technical single track. Feels very washed out, actually. From there it connects to #8 or #14.
The "C-course" is downhill double track with few features. There are some rollers that you can launch off of and a few berms and wall rides (natural) that you can play with if you have the skill, but it's pretty straightforward. C connects at the bottom with blue #9 and #10 which are both very windy and twisty. #10 passes you through a thrilling rock garden while #9 is big berms through the woods. There is a black section #15 at the bottom which is short and fun and very technical, but a lot of that part of the course is under construction right now so maps and actual trails don't totally line up.
And at the bottom there is a "Skill Up" area with a short lift and some simple berms and rollers to practice on. The green course also exits alongside this skill area through a collection of trails called the "Zekkei" trail. They are not technical but have some nice flow in and out of the woods.