Asamadai Sportsland is a gymkhana ground in Chiba Prefecture.
The facility is basically a big asphalted area of around 25000 m2 on which a route is set out with pylons. There are already 3 standard courses (please see on the bottom of this page).
In case no event is posted on the calendar, it is possible to do free driving on the gymkhana course. The price is 500 Yen admission to the ground and then 5000 Yen for half a day. Driving is possible between 9:00-11:55 in the morning and 13:00-15:55 in the afternoon.
The location is northeast of Narita airport approximately 1.5 hour by car. Public transport is also possible from Sawara Station in Katori city. It would take approximately 40 minutes by bus.
A link to the website can be found below:
http://www.asamadai-sl.sakura.ne.jp/
And a link to the location on Google Maps:
Asamadai Sportsland Google Maps link
The courses of Asamadai Sportsland:
