Prepare bean curd: In a saucepan combine water, 1/4 cup of the soy sauce and five-spice powder. Add bean curd and bring to a boil over high heat. Reduce heat to low and simmer 10 minutes. Remove saucepan from heat and let bean curd marinate in liquid, 1 hour. Using a slotted spoon, place bean curd in one layer on a plate lined with paper towels. Reserve cooking liquid. Cover bean curd with more towels, then weight with 5-pound weight. Bean curd must be pressed under weight at least 5 hours, or refrigerated with weight up to 24 hours.
Prepare duck: In a nonreactive bowl mix duck with garlic, the remaining 1/4 cup soy sauce, 1/4 cup of the Shao Hsing and sugar. Marinate overnight.
Heat oil in a large heavy-bottomed saute pan over medium-high heat. Add duck, skin-side down, and cook 5 minutes, or until well-browned. Turn and cook 2 minutes more. Remove duck to a plate and discard rendered fat. Place pan over high heat, and add remaining 1/2 cup Shao Hsing and reserved bean curd cooking liquid, stirring to scrape up any browned bits. Add ginger, scallions, chili peppers and star anise and bring to a boil. Place duck pieces in a sand pot (or an enamelware or cast iron pot) skin-side up. Using a slotted spoon, transfer ginger, scallions and spices to pot and scatter over duck pieces. Pour cooking liquid over duck to barely cover. You may not need to use all liquid. Bring to a boil over medium heat and simmer, basting occasionally, 1 hour. (If you use a sand pot, read instructions carefully. Be sure to use a flame tamer to prevent pot from cracking.)
Just before serving slice pressed bean curd into 1/4-inch thick slices. Add bean curd to pot and simmer 1 minute to heat through. In a cup, dissolve cornstarch in water to consistency of heavy cream. Using a slotted spoon, divide duck, bean curd and aromatics among 6 plates. Bring cooking liquid to a boil and add cornstarch mixture, stirring well until thickened. Taste for seasoning, then spoon sauce over duck.