In the upper Zora River you can pay 20 rupees to go on a canoe and shoot the jars. (dont worry, you get an unlimitede amout of arrows and bombs).You must get 25 points or higher to win a bomb bag. As you go down the river you see things that look like jars. You have to shoot those. The Yellow are worth 1 point and the red are worth two. You can zoom out to steer the canoe, but you don't have to steer it too much. If you run into something, you will lose 1 point. The river mostly steers you. (just my opinion, dont steer the canoe).