noun
sword testing; trying out a new blade
Historically, testing a sword's sharpness on a person or corpse; in modern contexts, it refers to cutting soaked straw targets (畳表) or bamboo to evaluate a blade.
刀鍛冶は新しく打った刀の試し斬りを行った。
The swordsmith performed a test cutting with the newly forged sword.
現代の試し斬りでは、畳表を巻いたものを斬ることが
In modern sword testing, rolled tatami mats are often cut.
試し打ち is a broader term for test striking or test firing, not limited to blades.
Compound of 試し (test) and 斬り (cutting with a blade). The practice dates back to the Edo period when swords were tested on condemned criminals or corpses.