I say unusual in the sense of Japan seems to be the only one to have solved the issue of how do you transport 2 kids on a bike not with "big box" like the dutch and subsequently the entire western world but via 2 seats, they're apparently very popular over there as a means of transportation.
as someone who worked hard to earn enough concussions to empty her brain of all thoughts i'm a little jealous that these kids are getting such a headstart on bimbofication