swordsmanship; sword technique; way of the sword
Refers to the skill, technique, or style of using a long sword (太刀). Often used in historical or martial arts contexts.
彼の太刀筋は見事で、誰も敵わなかった。
His swordsmanship was superb, and no one could match him.
Compound of 太刀 (たち, 'long sword') and 筋 (すじ, 'line, path, technique'). The exact historical derivation is uncertain, but the term likely arose in martial arts contexts to describe the 'line' or 'way' of the sword.