They (the USA) fucked up Japan pretty bad. Throughout the 70s-80s the USA was fearful of the rise of Japan, their incredible ability to usurp American businesses, and their growing trade deficit surplus, which they then rolled back into US T-bonds. From an American perspective, Japan was in the 70s what China is today.
In the early-80s, the Yen-to-dollar ratio was really high. This kicked off an inflationary asset bubble within the country that lasted for several years. Starting in 1985, the yen-to-dollar ratio collapsed, falling by half from mid ¥200s in just two years and reaching a low of ¥85 by 95.
Japan entered the Lost Decade as a result of this situation. The lost decade became two, then the GFC happened, bringing it to three decades.
It is suspected that this was the result of an intentional attack on the Japanese economy by US officials with the express intent to curb Japan's rising economic power.