It's late afternoon as my family and I motor into the Iya Valley, a remote region of western Tokushima Prefecture. Billed as many things — a lost paradise, a secret hideaway, a rural escape — by the area's tourism brochures, I find that no adjectives can accurately capture the interplay of light and water here. Sure, the rock formations that comprise the walls of the Oboke Gorge are unique enough to comment on themselves, but there is a magic to the way the fading rays of the sun glimmer on the turquoise water of the Yoshino River.

Thankfully, we're not too late to get a closer look at what goes into this photogenic formula. With tickets in hand, my husband and 4-year-old daughter and I wait patiently to board our Oboke Pleasure Cruise boat for a quick jaunt up this geologically fascinating cut in the earth. More intrepid thrill seekers can take to the Yoshino River's rapids, but with a toddler in tow, an adrenaline rush is not exactly on the agenda. The 30-minute cruise through sparsely peopled scenery suits us perfectly for this trip.

If you've ever wondered where the true hidden Japan lies, the Iya Valley would be a top contender. Ancient rocks from the sea floor compete for attention with soaring peaks that turn fiery in autumn. Villages dot the region like specks on the forested landscape, but some claim there may be more mythical yōkai (goblins, ghouls and monsters) living here now than actual people. White-water rafter, leaf peeper, legend hunter — all would feel fulfilled with an escape to this corner of central Shikoku.