noun
A craftsman who forges swords, especially traditional Japanese katana.
彼の祖父は有名な刀鍛冶だった。
His grandfather was a famous swordsmith.
鍛冶屋 is a general blacksmith, while 刀鍛冶 specifically forges swords.
Compound of 刀 (katana, 'sword') and 鍛冶 (kaji, 'smithing').