keicho koban (oval gold coin ) and keicho chogin (oval silver coin ), which can be considered as ryogoku kahei issued by ieyasu tokugawa , eventually established their position as an official currency cast by the government for the unification of the whole country , but were not made sufficiently available in the chiho (regions ) because a large amount of keicho gold and silver flowed out to foreign countries , failing in the nation-wide currency unification , and therefore , ryogoku kahei such as chiho hallmark silver issued by silver mines at various places , were still used in parallel , serving to fill the shortage of keicho gold and silver , silently allowed to circulate , and used by daimyo (japanese feudal lords ) of various provinces also as a means to exchange with keicho gold coins , the central currency at the time of sankin-kotai (daimyo ' s alternate-year residence in edo ). 最終的に徳川家康による領国貨幣とも言うべき慶長小判慶長丁銀が全国統一により公鋳貨幣としての地位を築くことになるが、多額に上る慶長金銀の海外流出などにより地方まで充分に行き渡らなかったため通貨の全国統一を達成するには至らず、依然、各地銀山から発行される極印銀などの領国貨幣が並行して通用し、国内で不足気味の慶長金銀を補佐する役割を果たしていたため幕府も流通を黙認し、また諸国大名が、参勤交代のとき中央貨幣である慶長金銀と交換するための手段としても用いられた。
