The Yayoi era (300BCE-300CE) of Japan created the founding of the rest of Japanese history.  an increase of weaving, rice farming, iron and bronze making.  The start of trade with china and Korea the takes off in the konfu era.  The imperial family that exist to this day was founded in the 6th century BCE but did not centralize the empire until later.  

A Dokatu bell similar to korean.  used for fertility rituals. late Yayoi period (ca. 4th century B.C.–3rd century A.D.)

http://www.metmuseum.org/toah/works-of-art/18.68

Storage jar, late Yayoi period (ca. 4th century B.C.–3rd century A.D.), ca. 100–200

http://www.metmuseum.org/toah/works-of-art/1975.268.375

Haniwa of an armored man used for in burals

http://www.bookmice.net/darkchilde/japan/yayoi.html

Bronze mirrors were introduced into Japan from China and Korea

Source: Pitt Rivers Museum Body Arts | Bronze mirror 

Yayoi period (circa 2nd century) 

Carved with two cutting edges and medial ridge running down the length of the blade, handle with hand guard, fitted stand

Horse use was prominent in  Yayoi era japan

Reconstructed grain storehouse. Reconstruction of Yayoi period remains at Toro in Shizuoka, Shizuoka Prefecture, Japan.

http://www.newworldencyclopedia.org/entry/Yayoi_culture

A Yayoi jar, first-third century, excavated in Kugahara, Ōta-ku, Tokyo, Tokyo National Museum.

http://www.newworldencyclopedia.org/entry/Yayoi_culture

The golden seal said to have been granted to the "King of Wa" by Emperor Guangwu of a Han in 57 CE. It is inscribedKing of Na of Wa in Han Dynasty

http://en.wikipedia.org/wiki/Yayoi_period

 Raised floor building at Yoshinogari, a Yayoi settlement (reconstructed)

http://www.newworldencyclopedia.org/entry/Yayoi_culture