The first time you see it, you stop breathing. There’s a river in Japan that doesn’t look like water. It looks like someone melted the sky and poured it into a canyon. They call it Niyodo Blue. You don’t admire it from a bridge. You zip up a wetsuit, climb down into the gorge, and slide into the blue itself. The water is so clear you watch fish drift beneath your own feet, your shadow floating on white stones three meters down. It’s on Shikoku. The island 90% of visitors skip. The most unforgettable color of your life is sitting on the island nobody chose.