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Hatsukokoro  |  SKU: HST-KAJNB2-GY21-OTMPSS

Hatsukokoro Kaijin Blue 2 Gyuto 210mm Migaki Curly Maple

Regular price $198.00

IMPORTANT: Carbon steel knives can rust or patina quickly if not cared for properly. They require regular cleaning, drying, and oiling. If you are unfamiliar with carbon steel maintenance, we recommend choosing a stainless steel option instead.

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Availability

  • St Peters, NSW —
    2 Bishop St, Unit 2, St Peters NSW 2044
  • Crows Nest, NSW —
    107 West St, Shop 1, Crows Nest NSW 2065
    Pickup only
  • Prahran, VIC —
    180 Commercial Road, Shop 1, Prahran VIC 3181
    Pickup only
Detailed Specifications
Line Hatsukokoro Kaijin Blue 2
Profile Gyuto / Chef's knife
Bevel Type Double Bevel
Weight 164 g | 5.8 oz
Edge Length 219 mm | 8 5/8″
Heel Height 48 mm | 1 57/64″
Width @ Heel 2.3 mm | 3/32″
Width @ Mid 2.0 mm | 5/64″
Width @ 1cm from Tip 0.6 mm | 1/32″
Steel Blue 2 / Aogami #2 | Carbon
Blade Construction Sanmai - Stainless Clad
Hardness (HRC) 61 - 63
Surface Finish Migaki
Handle Curly Maple with S/S Ferrule- Blue
Region Hyogo
Best for
  • Pro chefs
  • Enthusiasts
  • Free shipping for knives over AU$200 Australia wide.
  • World-wide shipping via DHL Express, 3 to 5 days.


Hatsukokoro Kaijin(海神, Sea God), is a rather budget friendly line for its name, it has a pretty plain look with polished edge and sandblasted bevel, and zero additional design feature. But I have to say, if your next knife purchase is all about performance, this can deliver it at a price that is very hard to beat.

The key in a good cutting knife is the combination of an edge that cuts aggressively and a bevel geometry that penetrates and releases off food smoothly, and Kaijin does both fairly well. The steel choice is Blue No.2, a carbon steel produced by Proterial that excels at producing a really “bitey” edge. This type of edge can slice open soft items like proteins and tough surfaces like skins, and it’s an experience that stainless steel just couldn’t deliver. 

The magic of simple carbon steel is, they can be heat treated to a higher hardness and still retain a more decent toughness than most of the conventional stainless steel, this means they can perform when the edge gets pretty thin. In this case, it is exactly what Kaijin did. The bevel of Kaijin gets sharpened to a very low thickness near the edge, and this thickness gradually increases, transitions into two parallel surfaces. This type of convex grind and an extremely low thickness behind the edge is the key in delivering a smooth food penetration and food release, and it’s not an exception in the case of Kaijin. Although in some cases the very thin slice of food would stick to the flat zone of the blade, this still outperformed most of the knives we’ve tested on potatoes outside of the ones with more complicated hand grinded bevel.

Completing the package is the latest dyed and stabilized blue curly maple handle, paired with an elegant stainless steel ferrule. This modern handle not only looks striking but also improves durability and balance, it is our interpretation of "the ocean", adding significant value and complete the blade into one refined package.

Despite the carbon steel core used on the Kaijin, I still consider it as a rather practical line as the cladding is stainless. So the downside of the line really is the small amount of care needed to keep the exposed core steel dry and clean and a rather delicate edge that can’t handle much of a beating. I recommend this knife to anyone who already has some experience on an entry level VG10 or other stainless steel, and looking to upgrade into a carbon steel. This Kaijin line would deliver the desired smooth cut while keeping the maintenance and cost very manageable.

Pros Cons
  • Great for professionals
  • Great artistic
  • Budget friendly
  • Relatively hard to sharpen
  • Prone to rust
Care Instruction
  1. Don't cut hard things! Japanese knives are brittle so bone hacking is a NO NO!
  2. Wash with neutral detergent after use, and wipe dry;
  3. Please don't wash knife with dishwasher, it will damage the wood handle;
  4. Be careful not to leave the knife close to a heat source for a long time;
  5. It is a lot more dangerous to cut with a blunt knife than a sharp knife!
  6. It is best to sharpen a Japanese knife regularly on a waterstone.
  7. Oil the (carbon) knife if storing for an extended period of time to prevent rust.

Hatsukokoro

Hatsukokoro, a knife brand from Amagasaki

Hatsukokoro (初心) is a knife brand from Amagasaki, Hyogo, launched in 2019. It is a brand rather than a forge: it works with knife makers instead of forging itself.

The name comes from the proverb 初心忘るべからず, roughly never forget your beginner's mind. For the same characters the brand chose the gentler reading hatsukokoro over shoshin.

The brand's own catalogue names the place behind some of its lines, and the maker behind a few: Shinkiro comes from Fukushima, and Hayabusa HAP40, Saihyo and Sunaarashi from Seki City, while for others the maker or the place stays private. Some of our listing titles also carry the maker alongside the brand, such as Hatsukokoro x Yoshikane and the Hatsukokoro x Yoshihiro Yauji collaboration.

The Hatsukokoro lines we list include both carbon and stainless steels. Our listings include Hayabusa in SG2 and Aogami Super, Saihyo in SG2 and Ginrei in Ginsan. Carbon steel kurouchi lines include Aosagi, Aokitae, Kurokaze and Kurogane.

“A knife brand from Amagasaki that works with knife makers rather than forging.”

Est. 2019 | 令和元年
Known for Lines made with partner makers, from Seki City to Fukushima
Website handk.co Instagram @handk_official Read more about Hatsukokoro

Hatsukokoro · Hyogo

Knife details

Frequently asked questions

Gyuto or santoku: which should I choose?

The gyuto came to Japan with the beef-eating culture of the Meiji era, and that is where its name comes from. Tojiro says it is used for all kinds of cooking, which is why it is also called the chef's knife.

The santoku is a household knife that combines the good points of the nakiri and the gyuto. Tojiro describes it as all-purpose, from vegetables to meat and fish, double-bevel and built on the same construction as a Western knife.

Choose a gyuto if you want more length and reach. Choose a santoku if you want a shorter all-purpose knife. Tojiro's own size figures: gyuto 150 to 210mm for household use and up to 360mm for professional use, santoku 165 to 170mm for household use.

What is a gyuto knife used for?

The gyuto (牛刀) is a chef's knife for all kinds of cooking, and it is basically double-bevel. A knife maker's guide says it came to Japan in the Meiji era with the culture of eating beef, which gave it its name, but it does not cut only meat.

A Japanese dictionary describes the gyuto as slimmer than a santoku, with a pointed tip, used widely for meat, fish and vegetables.

What gyuto length should I choose?

A knife maker's guide lists 150 to 210 mm, double-bevel, for home use, and 180 to 360 mm, single- or double-bevel, for professional kitchens.

We suggest starting with a 210 mm gyuto for a home kitchen, and stepping up to 240 mm if you regularly cut large pieces and have the board for it.

240mm vs 210mm gyuto: which size should I choose?

Get the 210mm. We only point people to a 240mm when they have about 45cm of usable board, cook in volume, and regularly break down big roasts or whole fish.

On the gyutos we've measured for our product pages, the extra length is real. As of October 2026, the 210mm gyutos we list have a median edge of 213mm from heel to tip, across the 111 we have measured; the 240mm ones have a median of 240mm, across 100. The 240s are also heavier, 212g against 175g at the median, and a touch taller at the heel, 50mm against 48mm, across the same 100 and 111 knives.

Weight overlaps between the two sizes. As of October 2026, 11 of the 100 measured 240s weigh less than the median 210 at 175g. The 240s we measured weigh 146 to 323g, and the 111 measured 210s 121 to 255g. The number in the name does not decide how heavy a knife is, so check the measured weight on the product page.

Japanese or German kitchen knives: which should I buy?

Our advice: choose a Japanese knife if you want the keenest edge and do not mind caring for a harder blade, and a German knife if you want a tougher, more forgiving knife you can hone casually and use for heavy prep. On two Japanese knife steels, the steel makers' own figures start at 60 HRC: Takefu Special Steel rates VG10 at 60 HRC or more, and Proterial lists the hardening hardness of Aogami 2 (Blue 2) as over 60 HRC.

Our care advice for a Japanese knife: keep it off bone, frozen food and very hard squash, and use a wooden or plastic board.

What is the flat spot on a knife, and is it the same as the "sweet spot"?

The flat spot is the straight run of edge from the heel towards the middle, the part that meets the board along its length. At our counter we call it the sweet spot; elsewhere "sweet spot" often means the balance point, so ask which one someone means.

Past the flat, the edge curves up towards the tip (the belly), which suits a swinging or pulling stroke. Sharpeners also say "flat spot" for a worn patch of edge, so when you mean the shape, "the flat part of the edge" is clearer.

Will a carbon steel knife rust, and how do I look after it?

Yes, carbon steels such as Aogami (Blue) and Shirogami (White) are not stainless steels, so left wet they can spot or rust.

Care is simple once it becomes habit. Wipe the blade as you go, especially after acidic food like citrus, tomato or onion. When you finish, wash it in warm water with a little soap and dry it straight away with a towel. Do not let it air dry, leave it in the sink or the dish rack, or put it in the dishwasher. Store it dry: on a magnetic strip, in a saya or in a block in a dry spot.

If the knife will sit unused for a while, wipe on a thin layer of oil before storing. In our video James shows that mineral oil can stand in for camellia (tsubaki) oil, and he picks one labelled medical grade; we list the Kitchen Knife / Cutting Board Mineral Oil Medical Grade for this. If you find light rust, lift it with a rust eraser and a little water, then dry and oil the blade; we list the CKK and Naniwa rust erasers.

What is the difference between Blue 2 and White 2 steel?

Proterial lists 1.05 to 1.15% carbon for both steels; its Blue 2 table lists 0.20 to 0.50% chromium and 1.00 to 1.50% tungsten, while its White 2 table lists neither.

Proterial describes White 2 as a carbon steel with minimum impurities and high hardness, and Blue 2 as an alloy steel with tungsten and chromium to improve heat-treatment properties and wear resistance, with a hardening hardness of over 60 HRC for both. In its Japanese materials, Proterial calls its Aogami (青紙) steels high-carbon steel (高炭素鋼). Neither steel is close to the JSSA's 10.5% minimum for stainless.

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