煙花是日本夏季的風物詩，一到夏季，孩子們都跑到公園、河畔點燃玩具煙花。日本曾是煙花的主要生產國之一。1999年，全國最後一家線香煙花工廠快將倒閉，日本的玩具煙花幾乎陷入只能依靠外國輸入的狀況。幸好福岡的筒井時正（Tsutsui Tokimasa）玩具花火製造所的第三代傳人筒井良太（Ryota Tsutsui），不甘心日本的傳統文化就此流失，在線香工廠快將倒閉之時，前往學習修行，並在其倒閉之後接收了所有技術與器材，將日本重要的傳統文化保存下來。
In one of the scenes in the Japanese movie Our Little Sister, Suzu, a love child, tells her friend Fuuta that she is now living with her half-sisters. Walking home on this summer’s night, Suzu confesses to Fuuta the uneasiness she had living with them due to her illegitimate identity. However, when she gets home, her sisters bring out a yukata and asks her to try it on. The four sisters gather in the backyard, light up some sparklers and adore the firework glows vibrantly and fades. The delicate firework creates a strong power to strengthen the bond among the sisters. Life is perhaps like firework, one has to seize the chance to embrace and admire its short-lived beauty. This scene is an adequate depiction of the subtle connection between firework and season, life and sensibility in the Japanese culture.
Firework is a Japanese summer tradition; it is almost a ritual for children go to park and riverside to light up firework to welcome the beginning of summer. Japan was once one of the main firework manufacturing countries. However, even the last Japanese sparkler factory had faced the risk of closing down in 1999, Japan now has to mostly rely on the import of small fireworks. In the face of the gradual disappearance of this Japanese tradition, Ryota Tsutsui, the third generation of the Tsutsui Tokimasa Manufacturer began to learn the production skill right before the closing down of the factory. He took in all the technique and equipment from the factory after its shut-down, therefore he managed to preserve this irreplaceable page of Japanese tradition.
Fireworks produced by the Tsutsui Tokimasa factory are innovative and elegant, for instance, the “flower” series, animal-shaped fireworks, as well as the “Mount Fuji firework” that imitates volcanic eruption, bursting out intense smoke before finishing off with strong flames. The products that they take pride in should be the East and West Sparklers — the East Sparkler that is made of paper represents Kantō region, the major region for paper manufacturing; the West Sparkler that is made of rice straw represents Kansai region, which is the home to plentiful paddy fields. The traditional Japanese firework manufacturing skill is a cherished memory shared by many of the older generation, the Tsutsui Tokimasa factory is the only place that has inherited such technique. The technique to produce this tiny, short-lived yet vibrant glow is guarded by the devotion of the Tsutsui Tokimasa factory.