Tabelog
https://gyazo.com/34957367e3229fe012c2f5182502d80a
It is the largest (and most popular) review app in Japan.
Use it to see reviews and recommendations for restaurants, bars, cafes, desserts, etc.
Be sure to read about Reviews and ratings in Japan because a 2.7 - 3.2/5 star place on Tabelog is likely to be really solid! Tabelog reviewers can be anonymous so they are typically rather honest or harsh.
Generally it has more reliable reviews than other services.
ben.icon
I recommend tabelog over other services because it has much better accuracy, but also it may have listings that aren't available elsewhere. Not every business is on Google Maps, for example.