A Japanese sword (日本刀 nihontō) is one of several types of traditionally made swords from Japan. Swords have been made from as early as the Kofun period, though generally "Japanese swords" refer to the curved blades made after the Heian period. There are many types of Japanese swords that differ by size, shape, field of application and method of manufacture. Some of the more commonly known types of Japanese swords are the katana, wakizashi, odachi, and tachi.[1]
日本刀,亦稱東洋刀或武士刀,依據形狀、尺寸分為太刀、打刀(刀)、脇差(脇指)、小太刀、短刀等。廣義上還包括長卷、薙刀、劍、槍等。在日本製刀人被稱作「刀工」、「刀匠」、或「刀鍛冶」。
日本刀的形態,從平安後期,經過鎌倉、南北朝、室町、安土桃山、江戶初期,中期,幕末的推移,出現了很大的變化。主要表現為從直刀到彎刀的的轉變,直刀適合砍劈,彎刀適宜劃割[1],之所以出現這樣的轉變,有論者認為可能是受蝦夷(愛奴人)的影響[2],或是戰鬥型態變遷造成[來源請求]。從平安末期開始,刀具形制便逐漸改變。鎌倉時期中期因為元日戰爭,日本刀因為戰備大量製作,偶有佳作產生,亦後世所稱的名器名物,同時制刀風格也開始活躍。
Source From https://zh.wikipedia.org/wiki/%E6%97%A5%E6%9C%AC%E5%88%80