In a large stockpot coated lightly with oil, sear the chicken and season.
In same pot, add onion, ginger, maitakes and bamboo shoots.
Deglaze with naturally brewed rice vinegar and naturally brewed Worcestershire sauce and add chicken stock.
Bring to a simmer and check for flavor.
Add the chicken back, scallions and sesame oil.
Season and check for flavor again.
Serve in bowls.