For Japan, walk in is very hard now. You should only try walk in if you have a lot of time and really don't want to spend any money at all
Highly suggest building a relationship with SA in Tokyo and visit once every 2-3 months. You don't need to spend much at all to build relationship with SA
Here are my offers this year:
Tokyo: 1 kelly 28, 1 birkin 30 (both are nice colors)
HK: nothing (4x spending as US/Japan. Still no offer, really bad service. Oh and no rodeo charm, very insulting)