https://www.youtube.com/watch?v=yvoUYEu3o-c

A Japanese Master Craftsman Taught Me To Make Senko Hanabi Fireworks

When I was young, and when Beijing was allowed to set off fireworks, I can remember a type of firework made from iron powder and oxidant, it will spark when set off, that spark came from the burning iron powder.

I saw that sparkler multiple times in Japanese animations, which are held inverted, and never realized they are a unique type of firework, until that Youtube video.

That is very ingenious.