Nothing has changed recently. Japan has had purpose-built bike lanes for decades. Where bike lanes have not or cannot be inserted, markings instruct cyclists to use the shoulder of an existing road. It depends on where you are.

It’s actually part of Japanese traffic law. Cyclist can use the sidewalk (are required to use the sidewalk) where there are no markings or lanes. But in places where lanes and marking exist, cyclist are required by law to use them.

The problem is those laws are completely unenforced. So I often experience someone buzzing me and my child on the sidewalk even though there’s a completely empty bike lane right next to it.