The history of Ancient Japan can be broken down into three distinct periods. The first period called Jōmon period is the time in from about 14,000 BC to 300 BC. The term "Jōmon" means "cord-patterned" in Japanese. It refers to the markings made on clay vessels and figures using sticks with cords wrapped around them which are characteristic of the Jōmon people.
The second period called Yayoi period is an era in the history of Japan traditionally dated 300 BC to 300 AD. It is named after the neighbourhood of Tokyo where archaeologists first uncovered artifacts and features from that era. Distinguishing characteristics of the Yayoi period include the appearance of new pottery styles and the start of an intensive rice agriculture in paddy fields. Yayoi culture flourished in a geographic area from southern Kyūshū to northern Honshū.
The last period called Kofun period of ancient Japanese history, beginning around AD 250, is named after the large tumulus burial mounds (kofun) that appeared at the time. The Kofun period saw the establishment of strong military states centered around powerful clans, and the establishment of the dominant Yamato polity centered in the Yamato and Kawachi provinces, from the 3rd century to the 7th century, origin of the Japanese imperial lineage. Japan started to send tributes to Imperial China in the 5th century. In the Chinese history records, the polity was called Wa and its five kings were recorded. Based upon the Chinese model, they developed a central administration and an imperial court system and its society was organized into occupation groups. Close relationships between the Three Kingdoms of Korea and Japan began during the middle of this period, around the end of the 4th century.
Written Chinese comprises Chinese characters used to represent spoken Chinese and the rules about how they are arranged and punctuated. It had a huge effect on the development of the written language of ancient Japan. Chinese characters are called kanji in Japanese. Kanji do not constitute an alphabet or a compact syllabary. Rather, the writing system is roughly logosyllabic; that is, each character generally represents either a complete one-syllable word (see logogram) or a single-syllable part of a word. Kanji themselves are often composed of parts that may represent physical objects or abstract notions. Written Chinese is one of the world's oldest active, continuously used writing systems. Many current Chinese characters have been traced back to the Shang Dynasty about 1200–1050 BC, but the process of creating characters is thought to have begun some centuries earlier. After a period of variation and evolution, Chinese characters were standardized under the Qin Dynasty (221–206 BC).
Kanji were first introduced into ancient Japan in the first half of the first millennium AD. At the time, Japanese had no native written system, and kanji were used for the most part to represent Japanese words with the corresponding meanings, rather than similar pronunciations. A notable exception to this rule was the system of man'yōgana, which used a small set of Chinese characters to help indicate pronunciation. The man'yōgana later developed into the phonetic alphabets, hiragana and katakana.
During the Yayoi period from about 300 BC to 300 AD, iron tools and weapons such as knives, axes, swords or spears, were introduced to Japan from Korea and China. Shortly after this event, Chinese, Korean, and eventually Japanese swordsmiths produced ironwork locally. Swords were forged to imitate Chinese blades: generally straight chokutō with faulty tempering. Worn slung from the waist, they were likely used as stabbing and slashing weapons. Swordmaking centers developed in Yamato, San'in and Mutsu where various types of blades such as tsurugi, tōsu and tachi were produced.
Flat double-edged (hira-zukuri) blades originated in the Kofun period, and around the mid-Kofun period swords evolved from thrusting to cutting weapons. Ancient swords were also religious objects according to the 8th century chronicles Nihon Shoki and Kojiki. In fact, one of the Imperial Regalia of Japan is a sword, and swords have been discovered in ancient tumuli or handed down as treasures of Shinto shrines or Buddhist temples. Few ancient blades (jokotō) exist because the iron has been corroded by humidity. The transition from straight jokotō or chokutō to deliberately curved, and much more refined Japanese swords (nihontō), occurred gradually over a long period of time, although few extant swords from the transition period exist.