Yeradzhi is a name on the map in the middle of the Karakum, the Black Sand desert that covers most of Turkmenistan. There is no town in the nearby list, which tells you most of what you need to know. The Karakum is one of the largest sand deserts in the world, with ridges, hollows, saxaul scrub and takyrs, the flat clay pans that bake hard in summer. It is cold in winter, brutally hot in summer, and when it rains the clay turns to grease.
The rides that start here connect to Repetek, which has a well-known desert reserve and research station, and to Thulli koshk, a ruined fortified house of the old caravan era. Repetek is famous for its saxaul forest and for the studies of desert wildlife that have been carried out there for decades. You may see lizards, tortoises and, with luck, gerbils at dusk. The old caravan routes crossed the desert between oases, with wells and fortified rest stops, and a ruin like Thulli koshk is a clue to how risky those journeys were.
This is serious country for a motorbike. Roads can be lonely, sand drifts onto the surface, and the nearest fuel may be a long way off. Turkmenistan has strict rules for foreign travellers, including guides, permits and approved routes, so plan this long before you land. Carry extra fuel if you are allowed to, extra water, and tell someone where you are going. Expect long distances between settlements and few places for food.
The reward is silence and space. The sand shifts from pale gold to rust through the day, and at dawn and dusk the light is low and warm. Wind is a factor, since it can carry sand across the road and reduce visibility. The best seasons are spring and autumn. In spring there may be a brief flush of green and flowers. Do not underestimate the heat or the scale, and treat this place with respect.