Kirameki woks are proudly made in Japan, recognized as a "dream frying cast iron wok" that keeps the best part of iron fry-pan while keeping rust away and maintenance easy. The inside and outside sides of iron material are special processing with fiberlike concave-convex. It is a metal series produced in Tsubamesanjo, Niigata Prefecture, known for its excellent metal processing technology. Wide surface area to receive heat due to unevenness and double fiber line design, heats up to the core of the food at once, and traps umami. Double fiber refers as a double fiber line technology applied on the surface of the wok, it helps to heat up to the core of the food at once, and traps umami. And Nitriding is a hardening process on top of double line fibre surface where atomic nitrogen is introduced into the surface of a ferrous alloy. It helps to maintain the hardness of the wok itself. It enables the wok not easier to rust and damage. KIRAMEKI uses special Nitrogen Treatment is a surface processing technology used for anti-rust of aircraft or automobile parts. Nitriding wok is also a pre-seasoned wok which is an upgrade version of double fibre line wok to help you achieve the delicious 0wok hei in Asian cuisine. A high quality product by Kirameki - 100% made in Japan. 99.7% High purity Iron Wok. Premium pre-seasoned wok Nitrogen Treatment for hardening process Wooden handle, anti-scalding and non-slip Not easy to stick and not easy to rust Surface guaranteed not to peel, blister, or crack when heat is used. Suitable for gas, electric, glass-ceramic, halogen, induction, grill. Fast heat distribution, not easy to rust Lightweight and Durable compared with other traditional wok