Not only limited to Japan – but bouldering has really taken off.
Bouldering is done outdoors with real boulders.
But, a way to train and have fun with just a pair of shoes are indoor climbing gyms.
The paths you can climb on the walls are noted with small colored tape.
Each color signifies a different level of difficulty.
You need special shoes for climbing too.
There’s many dedicated shops and staff willing to give you advice (in Japanese, of course).
A small bonus is that Japanese culture makes sharing public facilities awesome.
Always clean rental shoes, taking turns to climb patiently and entertainment like manga and kendama on site.