Oboke and Koboke
The lyrical names of Oboke and Koboke have given rise to much comment over the years: respectively, they mean "big steps dangerous" and "small steps dangerous", an apt description of the perils of traversing through these steep gorges on foot.
National Highway 32 winds its way along the Yoshino river through the pristine valley. Coming from Osaka, Kobe or Tokushima, take the expressway from Tokushima and exit at Ikeda. Then follow route 32 towards Kochi for about 20 kilometres to Oboke.
A tunnel also connects Oboke to the western Iya Valley (4 buses per day).
Both Oboke and Koboke have train stations, but trains that stop in Koboke are rare. Generally, it is strongly recommended to travel in this area by car, because if you get there by train, it's hard to get around and you will have to walk along a noisy road without sidewalks. It is also hard to find entry points for hiking trails without a car. The nearest car rentals unfortunately are located quite far away, in Marugame, Takamatsu or Tokushima. There are buses to the nearby Iya Valley, however, they run very sparsely, especially on weekdays (around 2 busses per day).
See & Do
There's one main reason to come to Oboke and Koboke: the rapids rushing through the gorge below. There are observation platforms on the highway and near the train stations if you're content to gaze from a distance, but more daring types will venture down onto the Yoshinogawa River for a sightseeing cruise (¥2000 for a one-hour loop), and more adventurous types yet will try their hand at white-water rafting in the class 4 rapids. The rapids are Japan`s biggest and most exciting with amazing rock formations and crystal clear waters all adding up to make a must-do adventure.
If you survive the experience without developing acute hydrophobia, both Oboke and Koboke have onsen hot springs offering more bubbling water to soak in.
In Oboke, Koboke and the Iya Valley you can try a delicious river fish salted and barbequed on a stick. The fish are called ayu and amego and are pretty good. Iya Valley is also famous for soba noodles, but they're not nearly as good as the udon in Kagawa.