港北区役所

This place puts any DMV back in the states to shame. It’s so easy to get anything done here. You have to come here to register your address when coming to Japan or moving into the ward, or before moving/​leaving, or to get health insurance, or to deal with your pension stuff, etc. So you’re definitely gonna have to go there at some point, so it’s nice its so easy. If your Japanese isn’t super strong they have some people working there who have English skills, or at the very least the guys walking around the floor have some basic broken English. Waits generally aren’t too crazy, and as long as you don’t have anything particularly complicated, your interaction shouldnt last more than a few minutes.
Very close to the 大倉山駅 on the 東横戦. While you’re there, they have a lovely cheap fruit and veggie market next to the big スーパー right next to the tracks.