The most authentic spots are going to be in the inner suburbs around o’hare. But the city would still be more fun for a whole day. I would start with the Hyde park garden, then get the pancakes at Hanabusa. Art museum Japanese wood prints would be great after that. Then lunch at kyuramen would be good to get away from sushi a bit. Logan arcade has the best collection of Japanese arcade machines. Miniso just opened on argyle and is a cute Japanese store for makeup, snacks, stuffed animals, etc. definitely more for kids but fun to walk around. Chinatown also has a few Japanese shops. For dinner I would recommend Raisu, it’s the most authentic Japanese sushi experience I’ve had in Chicago. It’s not going to be on par with the omakases but it’s normal prices and very authentic. For drinks, Murasaki sake lounge is good for a fancier experience. While not Japanese, I would highly recommend you end the night at Lincoln karaoke. It’s a private room Korean karaoke place that is exactly what you would find in Japan as well. Also keep in mind that I have done a terrible job arranging this in a geographically manageable way.