William While not exactly located in Kumamoto, Nagasaki has sent some heavy stuff our way, mostly thanks to the Unzen volcano. In 1792, the mountain collapsed, creating a “bathtub effect” in which tidal waves bounced between the two coasts. It has been estimated as one of the deadliest tidal waves in history.
It also created a whole lotta islands, and in Japanese, a “whole lotta” goes up to 99 (think of the American “These go to 11”). Out of the detritus emerged “Kujuku Shima” - “99 Islands.” (That’s likely an imprecise figure, but let’s stick with 99 - and it’s not to be confused with other locations whose island number also deserves the moniker of “99”.)
If you’re looking for an inexpensive summer vacation, the ferry from Kumamoto New Port to Shimabara (https://www.kyusho-ferry.co.jp/world/index_en.html) is affordable and worth the price in itself. Bring bread for the seagulls and a floatation device such as a raft or Morrey Boogie which you hopefully won’t need until you get there.