Difference between Japanese and foreign shell

Ex. Japanese round shell

Ex. ForeigniU.S.A.jcylindrical shell

Recently, we japanese usually saw foreign made shells at fireworks display in Japan. It not only depend on actively trade, but devise of sponsors and pyrotechnists who make display more enjoyable to add more variation in their direction. So we enjoy any foreign made shells that we had ever seen it.
Foreign made shells that shoot up in Japan, it seems very different from Japanese shells. We japanese think any fireworks like a a chrysanthemum or peony has round shape and blooming it in a circle. But almost foreign(Ex. America, Europe, Italy, Spain, Australia,etc.) made shells are not always bloom in a circle. Off cource there is a difference in method of shooting up or direction each other country. But there is a basically difference in shape of shells each other.
Please look at figure. There is completely different from each shape and structure. Both of them use cylindrical tube to shoot up, Japanese shells has roundly shape, Foreign made are cylindrical shape. Stars that pack into shells, are also different. Japanese star has round shape with some kind of layer of powders. Because of this structure, changeable color in burning. Foreign made stars are cylindrical or block shape, it made by only one kind of powder through the press(machine). So never change color in halfway.
In Japanese round shell, it scatter each stars on every side by breaking powder (call it Warikayaku) in center of shell and bloomig. In cylindrical shell, It off the top of cylinder and give off each contents to the air. You can understand each difference to look above two photos.
A merit of cylindrical shell, If they are same diametar, it possible to packing a lot of contents than round shell. And more, pile up some cylindrical shell to be one unit, and firing in order, it turn out more changeable direction.
Recently, there is coming to make round type shells not only Asian area but in Italy, England,etc. Of course, Asian every country making japanese style shells. These Asian shells ,mainly Chinese ,are actually export. In Japan, under 5 inch shells that made in China are go on increasing.

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