With over 100 years of history, the handcraft techniques of Omagari Hanabi are registered as a traditional craft of Akita Prefecture. In addition to the task to carry on their cultural significance, hanabi displays are expected to entertain and enchant people with a high level of creativity. In recent years, precise music synchronization, complex programing and a range of elaborate firing techniques have become the standard.
1. Hanabi Production Process (Warimono – #10 Shell Production)
Modern-day hanabi are commonly crafted in stages, with different experts in charge of each part of the process. Every step requires considerable precision, patience, and concentration. Some craftsmen say that the work comes together like dominos – every part of the production process needs to complete to light up the night sky beautifully. The following describes the process of making Warimono, a classic example of aerial hanabi.
1) Planning for Fireworks Competitions
Creating new fireworks is all about how and what goes inside the shells. In the case of dividing the production process, hanabi artists provide instructions on the size of stars (gunpowder grains) and the thickness of colored gunpowder layer in millimeters. They specify arrangements inside the shells, types of explosives to break them, and a way to wrap paper on the external side. All these elements determine how fireworks turn up in the night sky.
2) Making the Chemicals
Depending on the color and types of fireworks, materials such as the compounds inducing flame reaction (to color fireworks) and oxidant/fuel sources (to burn gunpowder) are weighed, mixed, and sifted. This process of creating explosives requires careful adjustments.
[Creating New Colors] How can we create new colors of fireworks… like a blue one, which the world has been pursuing for a long time? Even if we find the right balance of chemicals to create the color, would the same flame reaction occur in an aerial fireworks shell? Flammability, burning velocity, continuity of combustion, and safety – all these factors need to be considered. Colors appear differently based on distance. The challenge for new colors reveals the profoundness of fireworks supported by science.
3) Creating the Stars
Stars are created by moistening 2mm-diameter ceramic cores, covering them with the chemicals made during the previous production process, and pouring a liquid of chemicals dissolved in water in order to swell each grain. This work requires patience.
[To Create Stars that Changes in 3 Colors…] Each colored gunpowder layer contains different metal. For combustion to proceed from quickly igniting black gunpowder to the layers of colored ones, each of those metals needs an ignition agent that radiates higher heat than the reaction at the previous layer. Behind the changes of colors, there is a delicate and elaborate technique of creating seven layers within a star of 1cm diameter.
4) Drying the Stars
Stars covered with chemicals are dried under the sun in the summer and indoors with drying equipment in the winter. It is essential that the process is conducted manually to ensure even drying. The stars grow by 1mm a day by repeating processes 3 and 4.
5) Loading the Shells with the Stars
The stars are placed side by side against the inner surface of the paper-made hemisphere shell, and are organized in multiple layers with Japanese papers in-between. The explosives to disperse the stars are positioned at the center. The arrangement needs to be precise and symmetrical for the fireworks to form a sphere.
[Filling Stars for Non-Warimono Fireworks]
Components inside fireworks shells of Kowarimono and Pokamono often have their own fuse. They need different work from Warimono such as coating a solvent to ignite the multiple fuses. Contrary to such fireworks, Pokamono with a parachute needs a coated-paper cover to prevent the parachute from burning. Each firework requires a particular work.
6) Putting the Two Hemispheres Together
The two hemispheres filled with the stars and the explosives in a similar manner, with one of them attached with a fuse are placed together. The joint is fixed with paper tape, and the sphere is shaped.
7) Pasting the Shells
Craft paper cut into rectangles are glued on the surface of the shells with a pattern. Each company make its glue with rice flour or wheat flour. Depending on the shells, the number of sheets of paper differs. After the paper is glued, the shells are dried, and the paper is pasted again.
8) Finishing Touches
Lastly, the size and name get inscribed on every fireworks shells. They will be labeled, dried, and stored.
In order to synchronize the timing of shooting and fireworks dispersal with the music, it is imperative to program with computers.
[Listening to All Kinds of Music] Those who are in charge of music find the perfect song for any kind of fireworks by listening to all genre of music – from classical to rock, Latin, or pop. Some say that they memorize the music phrase by phrase, thinking about the types of fireworks and timings for several occasions. A pile of CDs they have highlights their effort.
10) Setting the Fireworks
Fireworks launchers and the shells are carried into the venue, and they get fixed in the order of the program. The fireworks shells and the explosives to launch them are placed inside the launchers, and quickly firing fuses are set for ignition.
The mainstream launching style today is remote electric ignition or autoignition by computer. Hanabi artists know if the fireworks successfully lit up when they hear the applause and the cheers.
[What “Hanten” Does]
Hanten is the Japanese short coat that hanabi artists wear when launching the fireworks. It not only displays their company name but also protects them from sparks of fire. They are made of thick fire-resistant materials, which show how dangerous the launching of fireworks can be.
2. Aerial Hanabi Safety
When launching fireworks, a no-trespassing area is set up as a safety distance between the launching area and the audience or the surrounding buildings. The safety distance differs by the size and type of fireworks, and each prefecture has its own rules. Sufficient knowledge is required to launch aerial fireworks, and the Japan Pyrotechnics Association issues the “Fireworks Consumption Security Notebook” for those who have them.
3. Structure of Warimono (Shaku-dama) “Yaeshin”
Warimono is the most basic fireworks. Inside its shells are grains of gunpowder called stars, which turns into threads of light, and the explosives to disperse the stars in the sky. They are placed in paper-made hemisphere shells with a fuse that ignites simultaneously when the shells are launched. Japanese papers are used to separate the stars and the explosives. Yaeshin draws three layers; a pistil at the center (created by pistil stars) and double petals (created by petal stars).
* Shaku-dama is a large 30cm-diameter shell. It is also called #10 shells.
4. Structure of Kowarimono (Shaku-dama) “Senrin”
Senrin is made of small shells containing the stars and the explosives inside a large shell (a shaku-dama in this display). The main fuse is ignited when launched, and the explosives within the small shells go off altogether after the larger outer shell disperses. The length of their fuses can adjust the timing for small shells to open up. Many chrysanthemums and peonies beautifully decorate the night sky.
*Shaku-dama is a large 30cm-diameter shell. It is also called #10 shells.
5. Structure of Pokamono (5-sun-dama) “Bunpou”
Pokamono contains various components inside its shell. The fuses leading to paper tubes inside the fireworks shells ignite simultaneously with the first explosion in the air. Subsequently, firing gunpowder at the center of the paper tubes explode to push out the stars from each end of the tubes. There are fillings like rice hulls and cotton seeds in the shells so that all the components in the shells are firmly settled.
* The 5-sun-dama is a 15cm-diameter fireworks shell. It is also called #5 shells.