# Guide to Knife Shopping ## Metal types ## White Carbon Steel #1 **(Shiroichi-ko, Shirogami #1)** > White steel #1 is the purest form of carbon, making it the closest material to tamahagane steel, which was originally used to craft Japanese swords. Forging a knife out of white steel #1 is extremely difficult and very few highly skilled craftsmen are still able to forge kitchen knives with this material, making knives made out of white steel #1 exceedly rare. Using a knife forged out of white steel #1 also requires great skill, as these knives are brittle and difficult to maintain. However knives forged out of this material will have the sharpest edge achievable. via [Korin](https://www.korin.com/about-carbon-knife-care) ## White Carbon Steel #2 (**Shironi-ko, Shirogami #2)**) > White steel #2 is the most commonly used type of white steel. This steel achieves a harmonious balance between sharpness and brittleness, making it easier to use than white steel #1. via [Korin](https://www.korin.com/about-carbon-knife-care) ## White Carbon Steel #3 **(Shirosan-ko, Yasuki-ko)** > White steel #3 has a slightly lower carbon content than white steel #2. The material is therefore not as hard or pure as other white steels, but if sharpened properly it can attain a similar edge. This grade of steel was developed and manufactured in Shimane prefecture in the Western region of Japan. via [Korin](https://www.korin.com/about-carbon-knife-care) ## ## Blue Super Steel (Aogami Super) > Aogami Super is a Hitachi “Yasugi” paper carbon steel—an enhanced Aogami with added tungsten, molybdenum, and vanadium that boost hardness, wear resistance, and mild corrosion resistance. It reaches 64–67 HRC (usually tempered to ~63–65) and offers outstanding edge retention, rivaling some stainless PM steels. Though the least tough of the Aogami series, it’s still durable for proper kitchen use. Fully reactive, it needs care to prevent rust but sharpens to a crisp, fine edge with moderate effort. > > Carbon (C): 1.4–1.5% | Tungsten (W): 2.0–2.5% | Molybdenum (Mo): 0.3–0.5% | Vanadium (V): 0.5% via [Bernal Cutlery](https://bernalcutlery.com/collections/gyuto-1/products/shiro-kamo-210mm-gyuto-stainless-clad-aogami-super?_pos=1&_fid=018dfb4c5&_ss=c) ## Blue Carbon Steel #2 (**Aoni-ko, Aogami #2)** > Blue steel #2 is a mixture of chromium, tungsten, and white steel #2. The addition of chromium and tungsten to white steel gives it added hardness, making it a good compromise for those who want a carbon knife with a longer edge retention. via [Korin](https://www.korin.com/about-carbon-knife-care)