Fry the tofu in some oil, and set aside. In a soup pot over medium heat combine vegetable stock or water, pineapple pieces, tomatoes, and water. Add the tofu. Cover and simmer for 10 minutes. Add celery, and season with soy sauce to taste. Bring to a simmer for 2 more minutes. Turn off heat. Serve with rice.

1 pound firm tofu cubes
2 1/2 vegetable stock or water
1 cup water
1/2 cup canned pineapple, unsweetened and diced
1 cup canned diced tomatoes
2 stalk celery, chopped
soy sauce to taste
oil