When you visit Japan, many people go to Tokyo then hop on the bullet train to visit Kyoto and Osaka and Nara. I do recommend visiting Kobe as well. It is only 30 minutes away from Osaka.
Here are things to do in Kobe
(1) Visit Kobe Port
(2) Visit Kobe Ijinkan Kitano-cho (Old Wester Settlement)
(3) Try little Kobe Beef
For more info https://plus.feel-kobe.jp