Heat the sesame oil in a medium skillet over medium heat. Add the ginger and cook, stirring for 1 minute. Add the bok choy and the mushrooms. Cover the skillet and cook for about 4 minutes, stirring occasionally.
Remove the lid and add the bamboo shoots, diced tofu, soy sauce, and garlic powder to the skillet. Turn the heat up slightly and cook the mixture, stirring often, for another 4 minutes, until the tofu has soaked up all of the juice from the pan.
Remove from the heat and season with salt and pepper to taste.