Beginning in the 1600s, the tokugawa shoguns who ruled japan tried to maintain stability and order by
a. increasing trade with europeans
b. conquering nearby countries to create barriers to invasion
c. developing a new style of writing that was not related to the earlier form of japanese writing, which had been inspired by chinese writing.
d. closing the country off from contact of the outside world to prevent disruption of foreigners.

The answer is D. The Tokugawa Bakufu was able to restore the stability of Japan during 1600 was by implementing Sakoku. Sakoku means a period of national isolation. No foreigner can enter Japan and no Japenese can leave Japan, if they do so, theywil be executed. Japan had secluded itself from the world due to the impendeng threat of the Spanish and Portuguese colonization and Chistianization after Kyushu was christianized. They were not totally close off to the world, in fact they were trading with a Dutch company, China and Korea in the various ports in Japan.

They weaken the south vietnamese army.