It's called Senko-hanabi, a traditional Japanese toy fireworks. Senko-Hanabi is always included in the packets of toy fireworks and are always done last to finish off the family fireworks which wouldn’t be complete without them. There is a sadness to Senko-hanabi. They evoke mono no aware, the flash of sadness at the beauty and briefness of life.ans a Japanese term for the awareness of impermanence.