This video, titled "[Niigata] Yuzawa Longboarding" (「新潟」湯沢ロングスケートボード), was released by "Downhill Baka" (ダウンヒルバカ).

There are many different kinds of skateboarding events.
One of them is downhill longboarding.
In this event, longboarders compete for the best time down the mountain pass.
The average speed down the mountain pass is between 60 to 70 km/h. At the fastest points, riders can reach up to 90 km/h.
The number of people who love skateboarding is still small in Japan, but those who do skate, love the sport.

The video shows longboarding in Yuzawa, Niigata Prefecture.
Check out the video to see how fast they go down a long downhill slope on their longboards.