Read the article. It isn't using the term "soft power" in the realpolitik sense, it's something else entirely. It's more of a meditation on culture and the search for meaning in life. It suggests that Westerners have forgotten what most other societies remember. It uses Japan as an example, but the idea isn't specific to Japan.
> It suggests that Westerners have forgotten what most other societies remember.
But she wrote books for japanese audience in Japanese. Wouldn't it imply that easterners have also forgotten it? How would her books be best sellers in 'other societies' if they already remember it.