How Konro Grills Are Made
The word ‘konro’ was originally used to describe a portable heat source for cooking, but these days in Japan, ‘konro’ describes a household gas burner like this one. That said, the ceramic charcoal grills that we sell at Knifewear are also referred to as ‘Konro’. The highly portable Shichirin Konro are perhaps the most popular shape of konro grill in Japan.
They’re so well-loved because you can grill vegetables and meat as you typically would over charcoal, but also you can use them to heat pots and pans! The Kanji for Shichirin (七輪) means seven rings, but when Japanese folks see these kanji, they only think of the konro. When Ariana Grande tried to get a tattoo saying seven rings in Japanese, it didn't go as planned.
The Konro grills we carry at Knifewear are made with diatomite. This sediment of diatomaceous earth forms after a huge number of phytoplankton die and sink down to the bottom of the ocean. During the sedimentation process, any organic matter from the phytoplankton is degraded, leaving glass-like shells. This resulting diatomite possesses a very porous texture. In Japan, this unique sediment can be found in the Noto peninsula, Ishikawa and some parts of Hokkaido.
A diatomite mine, the material konro grills are made from.
There are two different methods to make konro grills: Kiridashi and Nerimono.
In Japanese, Kiridashi means to ‘cut out’. Highly skilled craftspeople go into a diatomaceous earth mine and cut out the diatomite in cubic or cylindrical blocks. Back at their workshop, they carve the blocks into the konro grill shape, then bake them in kilns. Check out this video of the process. These types of Konro grills are about 2-3 times more expensive than our konros, due to the workmanship and effort that goes into making them. They’re also more durable because they are one piece, but they’re very hard to come by.
Our konro grills, on the other hand, are called Nerimono or ‘made from paste’. Basically, they are made with the same material but they grind the diatomaceous earth up, mix it with water, put it into molds, and bake it into blocks. The craftspeople then assemble them into the shapes that we carry. The big advantage of this method is that they can produce them much faster and a lot more affordably than the kiridashi konro. Nerimono konro functions just as well as Kiridashi konro, and this method also allows them to make larger sizes of konro!
Our nerimono konro grills are made by the company Kaginushi Kogyo. Since 1932, Kaginushi has operated a diatomite mine and konro workshop on Noto Peninsula, and today they're the best-known konro maker in the western world. On January 1, 2024, Noto Peninsula was hit by a magnitude 7.3 earthquake followed by a 5m Tsunami. Thousands of folks were affected, including our friends at Kaginushi Kogyo, who's factory and mine were damaged and flooded. Knifewear and our customers were able to raise $13,225 through knife sharpening proceeds for the Japan Red Cross, and through an outpouring of support, the area was able to recover. As of summer 2025, the folks at Kaginushi are still rebuilding, but they'll be back on their feet soon!
Blocks of Diatomite, used for making konros.
Kaginushi-made konro grills are the most popular ones around, from retailers of Japanese cookware like us to restaurants that cook over charcoal daily. I hope you enjoyed learning about this process, if you’d like to learn more about Konro grills we have a ton of other articles about them and how they work!
