Yahoo is a local search engine in Japan, but Yahoo actually uses Google’s search algorithm. Therefore, there is not much difference in rankings between Google and Yahoo.
Yahoo has been using Google’s search algorithm since 2010, so there is no difference in ranking from Google.
It may differ depending on the timing of the search. Also, Yahoo ads and Yahoo’s own services are displayed in organic search results, so they look different.
For SEO in Japan, you only need to care about Google.