1. Cut potatoes into 1-inch squares.
2. Cut carrots into half-moon shape.
3. Slice onions.
4. Cut tofu into 12 pieces.
5. Drain and wash shirataki noodles. Cut them in half.
6. Heat the vegetable oil in a medium saucepan over medium-high heat. Cook potatoes, carrots, and onions for 2 minutes. Add shirataki noodles.
7. Add water, Oyster-flavored sauce, soy sauce, sake, mirin, and sugar.
8. Let it cook for 10 minutes and gently add Tofu.
9. When the potatoes become almost ready, add string beans.