deep in the mountains; mountain recesses; heart of the mountains
Refers to remote, secluded areas far inside a mountain range, often with a poetic or literary feel. Compare みやま, which is more common in everyday use.
See also: 深山 (みやま)
He went deep into the mountains to train.
The stillness of the mountain recesses cleanses the soul.
深山 is a more literary word for deep, secluded mountains, whereas 山中 is a neutral, everyday term for being in the mountains.
deep mountain valleys
Sino-Japanese compound of 深 (しん, 'deep') and 山 (ざん, 'mountain'). The reading しんざん follows standard on'yomi patterns.