Special features of Japanese Fireworks
The expression "How beautiful!" says everything about the pleasures of watching fireworks.
As you know, the fireworks are made with gun powder. Nowadays, most of the powder types are made of synthetic chemicals.Fireworks are reactions of burning chemical compounds in the air.If fireworks were only blasts and flashes made by burning of chemical compounds, they might surprise people the first time, but they would not leave lasting impressions in people's minds.
Why do fireworks move us?
Not only do they have the power of the flashes and sounds of explosion, but they have the incomparable beauty that has been produced by the devoted Japanese pyrotechnic craftsmen who pursued the art for generations. Chemical reactions grew into a fine art.
Japanese fireworks are the most elaborate and gorgeous in the world. Generation after generation, the Japanese pyrotechnicians and craftsmen passed on the traditional technology that they put their heart and soul into, literally, at the risk of their lives.
Japanese(chrysanthemum type) round shell has the following three characteristics.
1. Bursts(blooms) into circles or globe shapes, spread colorful traces(petals) all around.
2. Changes colors of stars.
3. Bursts(blooms) into single, double or triple layered concentric globe.
Why do the stars burst(bloom) into globe shapes?
That comes from the globe shaped structure of round shells.（figure: ex.Shell with pistil） I made a short explanation for each part.
Note: Stars in the figure are colored for easier understanding. Original colors of stars are mostly black or silver. The color of stars does not come from the color of gun powder. If you would like to know more about the colors of star, please see "Color".
Mostly made of cardboard pressed to make a hollow half-globe shape. Two halves make a set.
Most of them are a mass of powder shaped into a ball. These are the main parts that make traces (petals) when the shell bursts (blooms.) The size of the packaged stars changes according to the size of shells.
Functions as a time switch to make shells burst at the right height in the sky. It is lighted at the moment of launching, and after burning for a certain time, the fire reaches the breaking powder in the center of the shell. The length of the fuse differs according to the size of the package.
Breaking powder(Warikayaku, Hadanyaku)
Its function is to break the package and to light all stars at once, and to scatter the stars in all directions.
There is still more to do after packaging the stars. Pieces of paper are pasted in layers on shells for extra strength of the package. The balance between the strength of the package and the power of the breaking powder is very important in order for the shells to burst into their maximum size. So the pasting of paper and the drying of shells are both important in the process of making fireworks.
Partition paper goes between stars and breaking powder to block each other. Japanese paper, "Washi or Gampishi", is mostly used.
A rope is strung through this cannon and the shell is loaded down in the mortars.
2. Why do the stars change color?
Basically, Japanese stars are ball shaped. A star has many layers of powder that burn into different colors. A star burns from outside to inside changing its color.
Please see "Color".or "I want to know more about stars" for more information.
3. Why Japanese shell has multi pistils?
Single pistil shells are called "Shin-iri"
Double pistil shells are called "Yaeshin"
Triple pistil shells are called "Mieshin"(photo right: Mieshin-kiku、from the center, silver, scarlet, blue and red turn to silver flash)
By the accomplishment of Yae-shin round shell, Japanese fireworks manufacturing technology reached its summit.
It is very difficult to make a round shell burst to have the same center point for each pistil. It needs a high manufacturing technology.
How do you count the petals or the pistils of a multi layered shell?
Shells with double pistils and triple pistils generally have a structure like the left figure. They have more sophisticated structure, like the inside of a watch, than single pistil shells. You can see these especially intricate round shells displayed at fireworks competitions.
All about Japanese fireworks
How to make the color of stars