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So you've read our Aogami vs Shirogami guide and decided blue steel is for you. Then you open a product page and the choice splits again: Aogami #1, Aogami #2, Aogami Super. Same family, three different steels — and the difference matters more than most shops let on. Here's the honest version.
Aogami (blue paper steel) is Hitachi's high-carbon tool steel — essentially their white steel with chromium and tungsten added. Those two elements make the steel tougher, more wear-resistant, and a little more forgiving to heat-treat. Everything in this article inherits that base: all three grades are reactive carbon steels that will patina, all three take a screaming sharp edge, and all three want to be wiped dry after use. (New to carbon steel? Read our care guide first.)
Mostly two things: carbon content and, in Super's case, a couple of extra alloying elements.
If you want a one-line mental model: #2 is the all-rounder, #1 trades a little toughness for edge life, Super turns everything up to eleven.
There's a reason most blue-steel knives you'll encounter are #2. It hardens reliably to around 61–63 HRC, sharpens quickly on any decent whetstone, and holds its edge noticeably longer than white steel. Blacksmiths love working with it, which also means you'll find it across every price point — from workhorse knives to hand-forged artisan pieces.
For most home cooks upgrading to their first carbon-steel Japanese knife, Aogami #2 is the answer. It gives you 90% of what the fancier grades offer with none of the drama.
The extra carbon in #1 pushes hardness and edge retention up a step. In day-to-day terms: you'll strop or touch up the edge less often, and it feels a touch more "glassy" and precise on the board. The trade-off is a marginally more brittle edge — micro-chipping becomes possible if you twist the blade on frozen food or bones (which, to be clear, you shouldn't do with any of these steels).
Aogami #1 is less common than #2, and makers tend to reserve it for mid-to-upper-tier lines. If you already own a carbon-steel knife and know you like a hard, long-holding edge, #1 is a lovely place to be.
Aogami Super (often shortened to AS) is technically its own recipe rather than just "more #1". The added vanadium and molybdenum give it fine grain, high hardness (commonly 63–65 HRC), and the best edge retention of any traditional Japanese carbon steel. A well-heat-treated AS blade keeps a working edge remarkably long, even through heavy prep.
The costs: it's the most chip-prone of the three in careless hands, it's slightly more stubborn on the stones (still far easier than powder steels), and it's usually the most expensive. It's also worth knowing that AS rewards good technique — a smooth push-cut, a wooden or plastic board, no lateral twisting. Give it that, and it's magic.
Browse our Aogami Super knives →
| Aogami #2 | Aogami #1 | Aogami Super | |
|---|---|---|---|
| Typical hardness | 61–63 HRC | 62–64 HRC | 63–65 HRC |
| Edge retention | Good | Better | Best |
| Toughness | Best | Good | Good, but least forgiving of abuse |
| Ease of sharpening | Easiest | Easy | Moderate |
| Price | $–$$ | $$ | $$–$$$ |
| Best for | First carbon-steel knife | Hard-edge fans | Enthusiasts who maintain their knives |
Honestly — no. A skilled smith's heat treatment does more for real-world performance than the jump from #2 to Super. A beautifully treated Aogami #2 from a forge like Nigara or Hatsukokoro's partner smiths will outcut a carelessly made AS blade every time. Use the steel grade to set expectations, then judge the individual knife: who forged it, how it's ground, how it feels in hand.
That's also why we list the steel and the maker on every product page — both halves of the story matter.
Still deciding between blue and white steel families? Start with Aogami vs Shirogami. Already know your steel but not your shape? Our knife shape guide has you covered.
