Imotojima, the younger sister, is a name that gives the Ogasawara islands a family feel, and the islands really do read like a family spread across the sea: Mukojima, Yomejima, Anijima, Imotojima and the rest.
The beauty is in the colour of the sea and the details of the reef. Around the islets, corals grow in shallow shelves, with parrotfish, butterflyfish and the occasional reef shark. Green turtles feed on the seagrass, and from about January to March humpback whales arrive to calve, sometimes surfacing right beside tour boats. Above water there are seabirds, with some species nesting on cliffs and boulders, and the vegetation includes endemic palms and shrubs adapted to wind and salt.
Getting to the chain is an expedition of its own. The ferry from Tokyo takes roughly a day, and the schedule is limited, so a visit requires several nights. People who come do so for the sea and for quiet, not for fast riding or sightseeing in the usual sense. On the main island of Chichijima there is a small town with fuel and food, and rented scooters or cars let you tour the short coastal roads, which wind between headlands and sandy coves.
Plan around the weather. Typhoons from late summer into autumn can cancel boats, and the sun is strong all year, so bring sun protection. Respect the rules, too: landing on protected islets generally requires permits and a registered guide, which keeps the ecosystem intact. That gentle restraint is part of why the place has stayed so pure.