Modern relations between the two countries are based on Vietnam 's developing economy and Japan 's role as an investor and foreign aid donor .
Vietnamese -- Japanese relations stretch back to the at least the 16th century , when the two countries engaged in friendly trade .
Modern relations between the two countries are based on Vietnamese 's developing economy and Japanese 's role as an investor and foreign aid donor .
Vietnamese -- Japanese relations stretch back to the at least the 16th century , when the two countries engaged in friendly trade .