National Route 275, which is parallel to Hokkaido's main North-South route (National Route 40), will take you to Horokanai-cho. A short one hour drive from Asahikawa, on the way you'll be able to enjoy some spectacular scenery. Lush green forest in spring and summer, surreal autumn colors in fall, and a clean white-out in winter.
Though there are many avenues to Horokanai, the best route is Hokkaido Route72 from Asahikawa. Driving through the thick forest, the views from top of the mountains are unreal.
Horokanai-cho is the biggest soba (buckwheat) producer by land-size and production volume in Japan. The soba fields are completely covered by attractive soba flowers from June, which in itself is worth a look.
Horokanai is home to Lake Shumarinai, a large man-made lake offering trout in summer and smelt in winter when the lake completely freezes over. This is also one of the finest camping locations close to Asahikawa, affording genuinely relaxed surroundings for lovers of the outdoors.