swordsmanship; skill with a sword
Refers to the technique or skill of wielding a sword, often in a martial context. Compare with 太刀筋, which can have a similar meaning.
See also: 太刀筋
His swordsmanship was superb, and no one could match him.
line of a sword cut; slash line
Describes the visible line or trajectory left by a sword tip when cutting through the air or an object. Often used in descriptions of sword techniques or in historical/fantasy contexts.
As the sword cut through the air, a sharp slash line gleamed.
Compound of 剣 (ken, 'sword') and 筋 (suji, 'line' or 'skill'). The exact historical derivation is uncertain, but the word likely arose in martial contexts to describe both the skill and the visible trace of a sword stroke.