Heat up wok and add some oil; Stir Fry the onion, garlic and celery along with about 2-3 Tablespoons of curry for about 2 minutes. Add the chicken and the potato and fry for about 5 more minutes, coating well then add the chicken broth, sugar, salt and pepper. Cover and simmer for about 15 minutes. Remove the mix with a slotted spoon, allowing it to drain the juice back into the pan and to this add about 1 Tablespoon Corn Starch. Bring to a boil and stir to thicken and adjust seasonings if desired. Serve over hot cooked rice.