Tired of hauling your stones to go club in your grandmother’s ancient Tupperware? Here is a bento box that appears to be sturdy, robust, about the right size, and relatively inexpensive at around US$30.
https://us.monbento.com/en/shop/lunch-b ... -grey.html
The two separate compartments might even be a bit large for 6-9mm stones at 7cm deep, 14cm square. That’s about 2-3/4” deep, 5-1/2” square. So not quite deep enough to safely hold real wooden go bowls.
I saw this bento reviewed on America’s Test Kitchens. If you put your stones In one of the two units, you could bring dinner, too.
https://youtu.be/R8YrhOW6BvI