Hokkaido and Okinawa are: width="28" fetchpriority="high" class="mx-2 mt-2 inline-block align-bottom"><img src="https://storage.googleapis.com/oshinoko-5xfoy/oshinoko-5xfoy/admin-console-images/1733828333235_1799eaca-2ce0-4df0-8953-8c165b2fd2c7.png" alt="" height="28" width="28" fetchpriority="high" class="mx-2 mt-2 inline-block align-bottom">Maybe?
I did a quick search to see what's famous in each region, but it seems like there are other candidates like Tanabata and fireworks...
I'm confident about Okinawa and Aomori!!

Children of the 47 Prefectures (Random Thoughts) Tohoku + α | Ripley's post