ridge line; ridge trail
Refers to the line along the top of a mountain ridge, often used in hiking and mountaineering contexts.
尾根筋を歩いて山頂を目指した。
We followed the ridge line to the summit.
この尾根筋は初心者向けの登山道だ。
This ridge trail is a hiking route for beginners.
Compound of 尾根 (one, 'ridge') and 筋 (すじ, 'line' or 'path').