Kocho Junisen

kōchō jūnisen (皇朝十二銭) (aka jūnizeni) is a general term for 12 types of copper coins minted in Japan under the Ritsuryo system from 708 (Wadō 1st year) to 963 (Ōwa 3rd year). All of the included coins are circular in shape, have a square hole in the center, and were worth 1 mon.

Coins

Image	Inscription	Kyūjitai	Shinjitai	Year of introduction (Julian calendar)
	Wadōkaichin	和同開珎	和同開珎	708
	Mannen Tsūhō	萬年通寳	万年通宝	760
	Jingū Kaihō	神功開寳	神功開宝	765
	Ryūhei Eihō	隆平永寳	隆平永宝	796
	Fuju Shinpō	富壽神寳	富寿神宝	818
	Jōwa Shōhō	承和昌寳	承和昌宝	835
	Chōnen Taihō	長年大寳	長年大宝	848
	Jōeki Shinpō	饒益神寳	饒益神宝	859
	Jōgan Eihō	貞觀永寳	貞観永宝	870
	Kanpyō Taihō	寛平大寳	寛平大宝	890
	Engi Tsūhō	延喜通寳	延喜通宝	907
	Kengen Taihō	乹元大寳	乾元大宝	958