History
The cliffs around Chosser (Chhoser) contain some of the thousands of hand-carved "sky caves" found throughout Upper Mustang — multi-chambered structures cut into soft conglomerate rock, some dating back over 2,000 years, whose original purpose (burial, meditation retreat, defensive refuge, or storage) is still debated by archaeologists and remains only partly excavated. Jhong Cave, the most accessible example, has been fitted with ladders and walkways for visitors. Nyphu Gompa, a still-active cave monastery, is built directly into the same cliff system and houses a small community of monks.
Stories & Legends
Local oral tradition holds that the caves were built by an ancient people fleeing invasion, retreating into the cliffs to defend the valley — a story that partially aligns with archaeological findings of the caves' defensive and burial uses. Others describe them as meditation retreats for early Buddhist practitioners seeking total isolation, a use that continues in a much smaller way at Nyphu today.
Practical Tips
An easy half-day trip from Lo Manthang, usually combined with Garphu and Tangge if time allows. Bring a headlamp for exploring the darker cave chambers.