If the U.S. dollar devalued against the yen during the 1980's that would be news to me.(posted 7464 days ago)I am 100% certain that during the 7 year period from 1980 to 1986 the US dollar rose sharply vs. most European currencies.
Still if a currency devalues then that country's products become cheaper and thus more competitive. Why? If you want to buy US good, first you need US dollars or their foreign or commodity equivalents. If the US dollar becomes less expensive US goods becomes less expensive too.
I hope this helps.
~Bob