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OIGEN’s craft of ironware dates back to 1852, at their foundry in Mizusawa, Iwate Prefecture, in northern Honshu. The current president, Oikawa Kuniko, is the fifth-generation descendant of founder Oikawa Genjuro, who began the company with kettles specially crafted for those living and working in Tohoku’s harsh winter climate.

Today, OIGEN’S hand-crafted range of pots, kettles and trivets are made for durability and style. Unlike easily replaceable pans and electronic kettles, each OIGEN product is designed to last a lifetime, crafted with the finest care through each stage of the process.

You can browse a selection of OIGEN products on the Japan House London Online Shop.


OIGEN has been producing craft ironware goods for over 150 years, beginning with ironware kettles which would heat both the water and air in people's homes during the cold, dry winter months. Though OIGEN strives to innovate, many of their products have been made in the same way for decades, using the skills of the local craftspeople who hand their knowledge down through the generations.  

Each product made at the OIGEN foundry passes through the hands of numerous artisans. The company’s philosophy - ‘relish the joy’ – reflects the pleasures of time taken to craft the perfect product. Of their craft methods, President Oikawa says: “Our products do not pop out at the push of a button. At the foundry, craftspeople check the sand with their own hands, check the molten iron with their own eyes, and check the heavy moulds moving up and down as sweat drips from their brows… Craftspeople in our factories take pride in creating things with their hands". 

Making cast iron

Cast iron is made by pouring bright orange molten iron ore into a sand mould. To create different sized objects, the temperature of the iron ore must be adjusted, and poured at a different speed. Large objects require higher temperatures and faster pouring methods, while for smaller objects the temperature can be reduced by around 200 degrees Celsius.

Controlling the temperature of the sand is also a key part of the crafting process. Artisans at OIGEN constantly check the sand’s temperature – which is sensitive to humidity and other weather-related variables – with their hands. The texture of these sand particles is visible on the surface of cast iron objects. Rather than decorate or embellish their goods, OIGEN uses these natural textures to showcase the quality and authenticity of their handmade products.

Kettles and teapots

Nambu tekki is the name given to the style of ironware kettles first made in Iwate Prefecture around 300 years ago. Initially, OIGEN's range began solely with kettles. Transporting the large, heavy kettles was a difficult process for OIGEN's salespeople, and meant they could only carry a few items at a time when visiting different regions. In order to innovate, OIGEN's artisans crafted small, more portable kettles to solve this issue - and thus the ironware teapot was born. By adding a tea strainer on the inside and charcoal paint on the outside, the iron teapot became a sought-after item throughout the whole of Japan.

Water boiled in these cast iron kettles takes on a delicate, soft palate - a result of the water's minerals clinging to the kettle's inner surfaces. This soft water is the perfect raw ingredient for making delicious tea and coffee. 


Trivets were initially developed to prevent marks and scorches appearing on surfaces from hot kettles and pots. In the OIGEN range, trivets go beyond this original function to focus not only on protection but also good design. Their trivet selection includes a variety of intricate and attractive iron weaves, helping them serve as decorative items. Trivets in Japan are now often given as gifts or used to adorn and embellish the walls of restaurants as an interior feature. 

Visiting the OIGEN factory

In the small area of Hadachō the distinctive scent of iron casting, along with the presence of ironware artisans strolling the streets, help create the atmosphere of a town with a long history of ironware production.

Visitors to Hadachō can explore the OIGEN Factory Shop, adjacent to the foundry, where rare, limited edition and outlet OIGEN products can be found. Display cases made from old work benches or abandoned factory furniture help give a sense of the company’s character. Visitors can enjoy free tea and coffee tastings with water boiled in OIGEN’s cast iron pots, while a café with magazines and children’s books offers a place to rest up. The OIGEN factory also offers tours for those wishing to learn more about the craft, available to book online on their website.

OIGEN at Japan House

In 2019, a selection of OIGEN products were on display in The Shop at Japan House London. The range included a series of teapots and kettles, from 130 ml through to larger 1.2 litre items, as well as several designs of trivets.

Visit our Online Shop to browse and buy a selection of OIGEN products.