Neighborhood Insignia

I find it fascinating at the neighborhood pride that is around me.
Chatan-Cho, my mihama (neighborhood) has a symbol and it is everywhere.
It is seen on buildings and manhole covers. My friend has it as a tattoo.

It is in the red above the three blue kanji.

In the center of the manhole cover.

At the 3 O'clock in the manhole cover.