1. Use a long, heavy knife to cut the squash into quarters. Discard the seeds and strings inside; peel each quarter and cut the flesh into 1/2-inch cubes. There should be about 4 1/2 cups.

2. Heat the oil in a large sauté pan or skillet over medium-high heat until the oil shimmers. Add the chicken and ginger and cook for about 2 minutes, stirring to break up clumps, until no pink remains in the chicken. Add the squash and cook for 2 to 3 minutes, stirring once or twice, until it is well coated. Add 2 1/2 cups of water and cook for 5 to 6 minutes; the squash should be submerged.

3. Combine the sugar and mirin in a measuring cup, stirring to dissolve the sugar, and add to the pan. Cook for 2 minutes, then add the tamari or soy sauce and cook for 8 to 10 minutes, until the liquid in the pan or skillet has reduced by half. The squash should be firm but tender and easily pierced with a fork.

4. Meanwhile, combine the remaining 1 1/2 tablespoons water with the potato starch or tapioca starch in a measuring cup and add to the pan. Cook for 30 seconds, stirring constantly; the sauce will thicken almost immediately and will take on a smooth sheen when it's done. Divide among individual bowls and serve hot.

Adapted from Kitchen Memories: A Legacy of Family Recipes from Around the World.