I got some question for this picture. This is not a combination of many shots, nor Multi Exposure work. This is taken by just only 2sec long exposure. Japanese fireworks are skilful and technical, so there is a lot of patterns to show their art. In the picture you see now, the fire starts to burst from the lake's surface to the sky gradually. If you open the camera's shutter adequately for the bursting moment, you can also take the image like this.