Put the rice in a strainer and wash under cold running water, while agitating with your hand, until the water runs mostly clear. Drain well and add to the bowl of a rice cooker, or into a heavy bottomed pot with a lid.
If you're using a rice cooker, you add the sake, soy mirin and salt and then add dashi until it reaches the 2 cup marker. Add the bamboo on top (don't mix it in) and cook according to the directions for your rice cooker.
If you're using a pot, add the washed rice, sake, soy sauce, mirin and salt to a pot and measure out the dashi. Add the bamboo on top (don't mix it in). Bring the mixture to a boil over high heat. Turn the heat down to low, cover with a lid and let the rice cook for 15 minutes. If it starts sounding like it's sizzling before the 15 minutes are up, your heat may have been too strong, or your lid may not have created a good seal. If the 15 minutes are mostly up, you can probably just turn off the heat and let the rice steam off the heat a little longer and you should be okay. If you still had a ways to go, you may want to add a bit of water and continue cooking the rice.
Once the rice is done, let it steam off the heat for at least 10 minutes.
After it's done steaming, mix everything together with a spatula and serve.