Many high-performance kitchen knives have blades made with a variant of white steel or blue steel. These are non-stainless high-carbon steels made in Japan by a few different manufacturers. The steels were originally named by the paper they were wrapped in at the factory, shirogami (white paper) and aogami (blue paper). There are different variants of both types on the market, each having different proportions of elements in their material composition. The most common types that consumers usually encounter are white #1 & #2, and blue #1, #2 & blue super.
So what is the difference and which is best for you, or should you stay away from both of them? White #1 has a high carbon content and a low level of impurities. When well made, white steel blades are known for superior sharpness and ease of re-sharpening, along with excellent edge retention. Master blacksmiths can bring white steel to its full potential. Some of our favorite makers using this steel are Teruyasu Fujiwara and Carter Cutlery.
Blue steel is more or less white steel with added Tungsten and Chromium, which create more wear-resistance and decrease reactivity/corrosion respectively. The knives of the Denka line by Fujiwara using blue super steel are amongst the hardest on the market, therefore require infrequent sharpening. However they are not as easy to hone as those in his Maboroshi line in white #1, therefore may be more difficult to own. Other makers who excel with blue steel are Tadafusa, MCUSTA, and Anryu knives.
White and blue steel knives are usually most appreciated by cautious users who appreciate the fine cutting ability and edge retention they offer. Caution is important because blades crafted from these steels are usually thin and brittle and can chip easily when using too much force or attempting to card hard materials. The performance of these steels also varies greatly by knife maker. In my experience Tadafusa’s blue steel knives hone just as easily as both MCUSTA’s blue super steel knives and Fujiwara’s white steel knives, but likely for different reasons (heat treatment and blade geometry).
So which is right for you? Getting any knife made from these types of steels from a reputable maker is usually a win-win situation, so choose the one you think you will enjoy the most!
(Steel composition and reference data sourced from Knife Steel Compositions App)