Rubber

• Japanese: 護謨 (gomu), ラバー (rabaa)

Rubber is an important modern material, used not only for car tires, boots, and shoe soles, but for a great many purposes. Though oft-overlooked, rubber was among the significant resources Imperial Japan sought to obtain by invading Indonesia and other parts of Southeast Asia in the early 1940s.

Rubber factories in the outskirts of New York City were among the many facilities toured in 1860 by Japan's first formal embassy to the United States.

The first rubber factory in Japan was opened in 1886 by the Mitatsuchi Rubber Company, established that same year. Japan's domestic rubber industry grew especially in the early decades of the 20th century, after Japan successfully renegotiated certain international treaties and regained tariff autonomy. At this time, the industry's primary products were bicycle tires, and shoes. As early as 1905, Japan was exporting some 300,000 pairs of rubber-soled shoes to Guangzhou alone. The British company J.P. Ingram established a factory in Kobe in 1908, and Dunlop in 1909. In 1918, vulcanization technology was introduced into Japan, and the industry began to grow even stronger.

Jika-tabi, the tall, rubber-soled, split-toed soft boots worn by construction workers, were introduced sometime before 1902. These were not only sold all across Japan, but were also exported in great quantities, to Hawaii and elsewhere. Rubber soles also began to be applied to the bottoms of traditionally-made zôri sandals. While leather shoes remained comparatively expensive for some time in Japan, various styles of rubber-soles shoes made from canvas or other fabrics became quite popular, including among top-level athletes, such as Japanese Olympic runners and tennis players competing at Wimbledon. After Japanese players wore canvas shoes at Wimbledon in 1923, their use began to catch on among athletes from other countries and before long became somewhat standard.

In the 1940s, as Imperial Japan occupied large portions of Southeast Asia, access to rubber trees was among the significant resources the government and military prized. Rubber was essential for the war machine, for tires, boots, and other uses.

Meanwhile, synthetic rubber was first developed by the Dupont company in 1931, but remained expensive to produce and in the late 1930s was only being mass-produced in the Soviet Union. Though synthetic rubber was actually a superior material in various ways, more resistant to wear-and-tear from weather, heat, and other factors, it only began to become more commercially viable around the world when World War II caused demand to skyrocket, and supply lines for natural rubber to become far more difficult.

All-rubber flip-flops such as are common today were first produced in Osaka in the early postwar years. By the mid-1950s, Japan was importing a significant amount of synthetic rubber, producing shoes at factories across the Kansai region (and elsewhere), and exporting flip-flops in industrial quantities to North and South America, and Southeast Asia. While conventional wisdom often says that flip-flops were made popular in the United States and elsewhere by members of the Occupation forces returning home, historians have suggested that Japanese-American communities (adopting the rubber flip-flops as only a small change from more traditional zôri) and surfing/beach culture in Hawaii and California may have played a more significant role. Hawaiian Statehood in 1959 was accompanied by a flash of popularity in the mainland United States for all things Hawaiian, and contributed further to the spread of the popularity of flip-flops.

References

• Martha Chaiklin, "Zôri and Flip-Flop Sandal, Japan/World," in Grace Lees-Maffei (ed.), Iconic Designs, London: Bloomsbury (2014), 199-201.