Rub inside of a 4-quart (3.5 L) heavy pot with cut sides of garlic, then discard garlic.
Add wine to pot and bring just to a simmer over moderate heat.
Stir together cornstarch, Kirsch and brandy.
Gradually add cheese to pot and cook, stirring constantly in a zigzag pattern (not a circular motion) to prevent cheese from balling up, until cheese is just melted and creamy (do not let boil).
Stir cornstarch mixture again and stir into fondue.
Bring fondue to a simmer and cook, stirring, until thickened, 5 to 8 minutes.
Transfer to fondue pot set over a flame and serve with bread for dipping.