Let’s look at the diagram below. It may be easier to understand what I am describing by referring to this diagram.
This is the timeline divided according to the historical period. The top short line is the time of the Joko-To period (上古刀). When we mention Japanese swords, we indicate swords made after the Heian Period (平安 794-1185). Swords made before the Heian period are called Joko-To(上古刀). Usually, Joko-To is in the category of the archaeological study. In the next chapter, Joko-To and the pre-Heian period sword will be described. The bottom timeline is the way we see in school history textbooks and other general history books. The middle timeline and the bottom line are almost the same, but the middle timeline is more useful for the sword study. My blog will follow the middle line. You will see this timeline diagram at the beginning of each chapter. Please keep checking back and forth with this diagram. We group together swords by its shapes, styles, and trends of the time.
The difference between Tachi (太刀), Katana (刀), Wakizashi (脇差), Tanto (短刀)
Swords made before the Muromachi period (before 1392) are called Tachi (太刀). Swords made after the Muromachi (室町) period are called Katana (刀) and Wakizashi (脇差). Tanto is a short dagger. Tanto was made throughout time. The difference between Tachi and Katana is how they were worn. Tachi was suspended from one’s waist belt, the blade side facing down. Swords maker’s name was inscribed facing outside on its hilt when it was worn. Katana and Wakizashi (called Daisho -大小- means large and small) were thrust between the belt and body both together, the blade side up. Swords maker’s name was inscribed facing outside on its handle when it was worn. When you face the maker’s inscription, if the blade comes on the right, that is Tachi. When you face the maker’s inscription, if the blade comes on left, that is Katana and Wakizashi.
Ko-To (古刀) Shin-To (新刀) Shinshin-To (新々刀) Gendai-To (現代刀)
Ko-To is the swords made from the Heian period(794-1192) to the beginning of the Keicho Era(1597-1615). Shin-To is the swords made from around Keicho Era (1596-1615) to Tenmei Era(1781- 1789). Shinshin-To is the swords made during Bakumatu time (幕末期 1789-1868). Gendai-To is the sword made after the Meiji Restoration (明治1868) until now. Keep in mind, even though the political history changed by a particular emperor or Shogun who became the top power at any given time in a precise day and year, sword style changed gradually.
*Strictly speaking, Bakumatsu time is from 1853 to 1869. But for sword classification, Bakumatsu time starts from Tenmei (天明1781 ) Era.