I think this heavily depends on location. At 7 my child can check nearly all the boxes for independent activities. My wife may not like it, but the surroundings are probably safer than anywhere else in the world. The only thing we don’t have is forests.
This is central Tokyo.
Kids still spend a lot of time on Roblox because everyone tends to be deathly afraid of letting them ring each other’s doorbells.
Seeing tiny tiny kids walking around is one of my favourite qualities of Japanese life, and on the flipside I sensed a quiet but shared responsibility/interest everyone took in making sure no harm befell the child on their journey. One the purest luxuries of living in such a high trust society
I also live in Suginami! There's always a lot of kids running around together, especially after school, but that feels quite normal for anywhere in Japan, no?
In Los Angeles we let our 8 year old walk half a mile to school and someone called the cops on us.