I my opinion, if you can stop the
Plaza accord of 1985 from happening and avoid the Bank of Japan's monetary easing policy of the mid 1980s (they almost halved the discount rate in one year) you butterfly the price asset bubble entirely.
The problem is that, by doing that, you won't get the period of massive growth that caused these ideas of "Japan taking over the world" to form in the first place, and you're just left with shitty growth rates througout most of the 80s and 90s (assuming the monetary and financial sectors remain tightly regulated). Now, this is still definitely a net positive, as you avoid the country falling into a pretty nasty recession, but still doesn't provide us with the conditions for a modern Japanene "wank".
To get the Japanese economy to grow quickly in the 21st century, you need to solve of a series of social problems that (IOTL) do not seem to be going away anytime soon, including the declining birthrates, the sexism that is keeping women out of the workforce, the unwillingness to take in immigrants, static corporate culture and abysmal enforcement of worker's rights (which leads to a ridiculously overworked and unproductive workforce).
Perhaps the best way to get this would be to manufacture a lot of corruption scandals in the late 70s and early 80s (there were actually quite a few IOTL, we probably just need a little bit more) so that the LDP might become discredited in a way that allows the socialist party to come into power. Under a JSP government, the monetary and financial sectors would remain tightly regulated, organized labour and worker's rights would get a major boost, allowing the most exploitative aspects of Japanese work culture to be addressed, the keiretsus may get broken up and there's a possibility of social liberalization. The only problem is that such a massive shake up of Japanese society may lead to a lot of instability, which would obviously hurt the economy. But if the changes get done and endure, it will robably be worth it in the long run.