In a large stock pot combine chicken broth, potatoes, celery, carrots and onion. Cover and bring to a slow boil for 15 minutes, or until the vegetables are tender.
In a medium sauce pan melt butter over low heat, add flour and stir until smooth. Let simmer for 1 minute and then increase temperature to medium. Stir mixture constantly, while gradually adding milk. Continue to stir until thick and bubbly.
Add flour mixture to vegetables. Add soy sauce and then gently stir in cheese. Continue to stir until cheese is completely melted.