Why did china and japan isolate themselves from european trade?

Did not like Western influence--traders brought Christianity and Western culture with them that the Chinese and Japanese did not like. 

Western traders often came with goods and Christian missionaries. The influence of Christianity influence Asian cultures and was viewed as a negative to the culture of China and Japan. The isolation occurred as an attempt to remove Western influence from the countries. 

“destroyers for bases agreement in the destroyers for bases agreement between the united states and the united kingdom on september 2, 1940, fifty caldwell , wickes, and clemson class us navy destroyers were transferred to the toyalbnavy from the united states navy in exchange for land rights on british possessions.” i hope this you .