Gassan school yoroi-doshi tanto. Signed "Yoshiteru", c. 1865, 0.5 in (13 mm) motogasane, (blade thickness) at the hamachi (the notch at the beginning of the cutting edge), 10 in (250 mm) nagasa (cutting edge), "ayasugi hada” which looks like a series of undulating rolling waves.
Theyoroi-dōshi (鎧通し), "armor piercer"[1][2] or "mail piercer",[3] is one of the traditionally madeJapanese swords (nihontō) that were worn by thesamurai class as a weapon in feudal Japan.
Theyoroi-dōshi is an extra thicktantō, a short sword, which appeared in theSengoku period (late Muromachi) of the 14th and 15th centuries.[4] Theyoroi-dōshi was made for piercing armour[5] and for stabbing while grappling in close quarters. The blade was generally from 20 to 30 cm (7.9 to 11.8 in) in length, but some examples could be shorter than 15 cm (5.9 in), with a "taperingmihaba,iori-mune, thickkasane at the top, and thinkasane at the bottom and occasionallymoroha-zukuri construction".[4] Themotogasane (blade thickness) at themunemachi (the notch at the beginning of the back edge of the blade) can be up to 1 cm (0.39 in) thick, which is characteristic of theyoroi-dōshi. The extra thickness at the spine of the blade distinguishes theyoroi-dōshi from a standard tantō blade.
Yoroi-dōshi were worn inside the belt on the back or on the right side[1] with the hilt toward the front and the edge upward. Due to being worn on the right, the blade would have been drawn using the left hand, giving rise to the alternate name ofmetezashi (馬手差),[6] or "horse-hand (i.e. rein-hand, i.e. left-hand) blade".
