What is Kurashikizome®?
In striving to be a more ethically responsible and sustainable brand, we are continually exploring eco-conscious manufacturing processes that reduce the environmental impact of producing Iron Heart clothing. One such approach is the use of Kurashikizome®-dyed fabrics.



The Kurashikizome® Story


For centuries, Japan’s Okayama and Hiroshima Prefectures — historically known as the Bicchu-Bingo region — have been synonymous with textile production. The salt-bed farmland of the area proved unsuitable for rice cultivation but ideal for cotton, laying the foundation for a rich textile tradition.

Today, the Kojima district of modern-day Kurashiki City remains a hotbed of textile craftsmanship, world-renowned for its selvedge denim. It was here, in 1954, that the Okayama Textile Dyeing Industry Cooperative Association was founded — the parent organisation behind Kurashikizome®. 

At the time, its role was to develop and pioneer new dyeing technologies as Japan rebuilt its post-war economy. However, in recent years, rising global awareness of environmental issues has called for the creation of the Kurashiki Dyeing Promotion Committee — dedicated to improving safety and sustainability standards within Japan’s textile industry. Of course, they needed a catchier name for this initiative. Hence, the Kurashikizome® trademark was registered.





…but what is Kurashikizome® Dyeing?
Many Kurashikizome® textile processors operate in the Kojima and Bizen areas of Okayama Prefecture. Some specialise in traditional dyeing methods using organically sourced pigments such as natural indigo, while others utilise modern synthetics. Kurashikizome® should be thought of less as a dyeing technique and more as a safety certification — an eco-friendly seal of approval.

The textile industry is estimated to account for around 25% of the world’s chemical use, some of which includes harmful carcinogens and allergy-inducing substances. To address this, Kurashikizome® has adopted the international ZDHC MRSL V2.0 regulations — far stricter than the current Japanese standard. This bans the use of many dangerous substances in manufacturing, ensuring greater worker safety and reducing environmental impact through improved wastewater treatment.

Since wastewater from Kurashiki City flows directly into the Seto Inland Sea, a designated national park, purification standards must be higher than in other regions of Japan. As a result, all manufacturers dyeing textiles under the Kurashikizome® standard minimise water usage, and all wastewater is thoroughly purified before being returned to nature. To ensure compliance, regular quality inspections are carried out by the Nissenken Quality Evaluation Centre, a globally recognised Oeko-Tex® certified inspection organisation.

Put simply, if a fabric bears the Kurashikizome® safety mark, you can rest assured it has been dyed and processed according to the highest safety and environmental standards in Japan.