added by archaeologs Metal tools are first reliably documented in Japan as continental imports about the same time as wet-rice cultivation was established in northern Kyushu around 300 bc. By the middle of the Yayoi period, in the 1st century ad, bronze bells and weapons that were much larger than their continental prototypes were cast in Japan, evidently for ceremonial purposes. Stone moulds and the tips of bellows have been found, but no smelting site of this age is known. Tin and copper do not seem to have been mined in Japan until the late 7th century. Iron axes and sickles replaced the stone counterparts by the end of the Yayoi period c300 ad. Hoes and spades had iron tips by this time. Since these are in styles with no parallel in Korea or China, they are considered to have been manufactured in Japan by itinerant blacksmiths. Here again, we do not known where the ores were mined and smelted. It is possible that the Yayoi people relied on outside sources, and the increasing indications of conflicts between Yayoi communities may be due in part to the competition to secure a supply of iron, for which there was growing demand. A greater variety of iron implements was used during the next few centuries when large burial mounds (kofun) and irrigation canals were built. Quantities of iron weapons and horse-trappings were deposited as burial offerings. Blacksmiths’ equipment has also been found in the mounds. Throughout this time there were contacts with the continent, and new techniques for making body armour, for example, were introduced either as imports or by migrant artisans. Smelting sites dating to the 8th century are known and authorities believe that iron smelting was probably practised in Japan in the 6th and 7th centuries.
The Macmillan dictionary of archaeology, Ruth D. Whitehouse, 1983