According to the latest Apple Maps acknowledgements page, last updated on 8/10/15, Tablelog.com, a Japanese restaurant guide, is now a business listings data supplier to Apple Maps. As you can see below, the implementation is identical to Yelp’s:
As best I can tell Tabelog content trumps Yelp and TripAdvisor when it has a review for a business. Yelp appears to have a fairly limited set of Japanese reviews so it makes sense that Apple would add focused regional content partners. I expect by this time next year Apple will have added content partners like this in every major country and service category.