Kogarasu-maru-zukuri (小烏丸造り) is a unique and extremely rare blade geometry that blends both Japanese and early Chinese sword designs. It is best known for its use in the legendary Kogarasu-maru (小烏丸, “Little Crow”), a unique tachi attributed to the Heian-period swordsmith Amakuni (天国). This style combines elements of both shinogi-zukuri (鎬造り, traditional Japanese curved blade) and moroha-zukuri (諸刃造り, double-edged blade).