ies ▁and ▁en vo ys ▁visited ▁Asian ▁states , ▁New ▁Spain ▁( now ▁Mexico ), ▁and ▁Europe . ▁This ▁period ▁was ▁also ▁noted ▁for ▁the ▁large ▁number ▁of ▁foreign ▁trad ers ▁and ▁pir ates ▁who ▁were ▁resident ▁in ▁Japan ▁and ▁active ▁in ▁Japanese ▁waters . ▁ ▁The ▁term ▁s ak oku ▁origin ates ▁from ▁the ▁manuscript ▁work ▁ ▁written ▁by ▁Japanese ▁astronom er ▁and ▁transl ator ▁Sh iz uki ▁T ada o ▁in ▁ 1 8 0 1 . ▁Sh iz uki ▁invent ed ▁the ▁word ▁while ▁transl ating ▁the ▁works ▁of ▁the ▁ 1 7 th - century ▁German ▁trav eller ▁Engel bert ▁Ka emp fer ▁concerning ▁Japan . ▁ ▁Japan ▁was ▁not ▁completely ▁isolated ▁under ▁the ▁s ak oku ▁policy . ▁It ▁was ▁a ▁system ▁in ▁which ▁strict ▁reg ulations ▁were ▁applied ▁to ▁commerce ▁and ▁foreign ▁relations ▁by ▁the ▁sh og un ate ▁and ▁by ▁certain ▁fe ud al ▁domains ▁( han ). ▁There ▁was ▁extensive ▁trade ▁with ▁China ▁through ▁the ▁port ▁of ▁Nag as aki , ▁in ▁the ▁far ▁west ▁of ▁Japan , ▁with ▁a ▁resident ial ▁area ▁for ▁the ▁Chinese . ▁The ▁policy ▁stated ▁that ▁the ▁only ▁European ▁influence ▁permitted ▁was ▁the ▁Dutch ▁factory ▁at ▁De j ima ▁in ▁Nag as aki . ▁Western ▁scientific , ▁technical ▁and ▁medical ▁innov ations ▁did ▁flow ▁into ▁Japan ▁through ▁Rang aku ▁(" D utch ▁learning "). ▁Trade ▁with ▁Korea ▁was ▁limited ▁to ▁the ▁Ts ush ima ▁Domain ▁( today ▁part ▁of ▁Nag as aki ▁Pref ect ure ). ▁Trade ▁with ▁the ▁A