HAP-40 Petty Black 135mm (5.3") [Tottori Sand]
HAP-40 Petty Black 135mm (5.3") [Tottori Sand]
HAP-40 Petty Black 135mm (5.3") [Tottori Sand]
€ 255.00

HAP-40 Petty Black 135mm (5.3") [Tottori Sand]

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HAP-40 Petty Black 135mm (5.3") is a small kitchen knife from our HAP-40 series which we designed in collaboration with the Yoshida Hamono smithy. With this series, we fused Japanese tradition and knowledge of blade design and materials processing, and what came out is a versatile kitchen knife made of powder steel that is simple to use and maintain. To top it off, it boasts incredible properties, characteristic of only the best performing and most practical Japanese blades!

HAP-40 Petty Black embodies the best characteristics we could possibly expect from a kitchen knife:

  • The shape of the blade allows for work on the cutting board, as well as for the in-hand use.
  • The blade tapers off towards the tip and lends itself perfectly to precise work with food.
  • Fine – and extremely long-lasting – sharpness.
  • Very hard powder steel with a hardness of 68 HRC. 
  • Simple maintenance and sharpening.

 

BLADE SHAPE:
Petty or utility knives are basically a smaller version of gyutos or chef's knives, intended for all those smaller tasks where larger and wider knives are deemed unwieldy. A must-have in every kitchen, this small general-purpose knife is used for peeling and slicing fruit and vegetables, while its compact size and a relatively narrow blade also makes it very nimble and thus perfect for filleting fish, cutting poultry, slicing smaller pieces of dry meats and trimming meat. The blade is 135mm (5.3") long.

HANDLE:
We paired this HAP-40 knife with our own Tottori Sand handle. It’s a traditional Japanese Wa handle with a colorful twist, resembling the largest sand dunes in Japan - Tottori! A universal, octagonal shape comfortably fits in the hands of both right- and left-handed users. It offers a firm grip for easy and comfortable use.

The handle is made of maple burl wood. It undergoes a special procedure of stabilization with resin, which ensures a very long service life of the handle. During this process of stabilization, a color pigment is added which is absorbed in the wood fibers. After the final treatment and polishing, the handle reveals the grain of the wood. Blocks of maple burl with irregular and non-uniform structures are used so the dye can penetrate the wood in different ways, creating unique patterns. This makes every handle one-of-a-kind.

☝️ Colors and patterns of handles will slightly vary from what is seen in the pictures. If you would like a particular color hue/pattern, contact us at support@sharpedgeshop.com before placing the order.

STEEL:
The secret of this knife lies in extremely (68 HRC!) hard core made of a somewhat exotic and currently one of the most mysterious and attractive steels produced in Japan (at least as far as kitchen knives are concerned): Hitachi’s HAP-40 steel that fits into the category of modern and technologically advanced steels. HAP-40 is fine-grained enough to sharpen very well, and knives from this steel keep their sharpness three to five times longer than traditional knives. An interesting fact is that, considering it is a powder steel, it has an extremely small content of chromium (around 4%) and can react as a high-carbon steel in specific circumstances.

This steel is heat-treated to an incredible 68 HRC, yet it can still be relatively easily sharpened on whetstones. It is extremely tough, and so not as likely to chip along the edge as the steel used in traditional knives.

🦉 As the technological development progresses, many new types of steel (ZDP-189, HAP-40, R2, Super X etc.) have come to light. They rate as high as 64-68 on the Rockwell scale (HRC) and possess staggering properties. Knives carefully crafted from powdered steel are the crème de la crème of kitchen tools and offer incredible cutting performance and edge retention.

Higher hardness value in knives means..?

✅ Higher hardness value ➨ long-lasting sharpness
✅ Higher hardness value ➨ thinner blade
❌ Higher hardness value ➨ higher brittleness

 More about HRC and hardness here!

Blacksmiths counter the brittleness of material that a higher value of HRC involves with special composition of the knife. The blades are laminated which means that they are not composed of only one type of steel but several layers of different steels. In the case of HAP-40 series, Osamu-san chose a WARIKOMI (also called “split and insert”) method. A glowing hot piece of iron is split and a piece of steel is inserted. The new material is now forged into one piece composed of a very hard steel core in a jacket of two external layers of softer, stainless steel. This creates a highly durable kitchen knife with a slightly more pliable core. The main advantage of these knives is that they are thin, sharp and retain their edge very well.

Lamination is a very challenging process in steel processing, therefore most blacksmiths buy already laminated steel sheets which they made into blades. HAP-40 is known as an incredibly demanding material to process, forge and quench and so remains a rare component in Japanese knives despite its stellar characteristics. Yoshida Hamono has a wealth of experience in processing powder steels and is also the only smithy that laminates its own ZDP-189 and HAP-40 steels, allowing it to adjust the method of lamination to the shape of the blade.

 Are you interested in learning more about blade construction and lamination? Read our article Blade construction: Lamination

Regardless of the high HRC value of HAP-40 steel, its chemical composition ensures decreased brittleness, while a low content of chromium means that it can acquire a patina!

COMPOSITION: 1.27–1.37% carbon (C), 3.70–4.70% chromium (Cr), 5.60–6.40% tungsten (W), 4.60–5.40% molybdenum (Mo), 2.80–3.30% vanadium (V) and 7.50–8.50% cobalt (Co).

If your work in the kitchen calls for a knife with good edge retention, HAP-40 steel offers a good alternative and an upgrade to ZDP-189 steel. We mostly had in mind professional chefs when choosing the material, but undoubtedly it will be a joy to wield by all serious knife enthusiasts, especially those who appreciate exotic and collectors’ items.

GEOMETRY:
It has a double bevel (symmetrical) blade and, according to its cross-section and the location of the shinogi line (where the angle of the surface changes), its shape is concave:

→ The part of the blade below the shinogi line is of concave shape. This kind of concave or hollow grinds finish in a very thin and extremely sharp point, so the blade remains sharp for a very long time despite frequent sharpening. This thin profile gives the impression that a knife is sharp even though it’s already ripe for sharpening.

BLADE FINISH:
The blade has a dark finish which is the reason why this look is also called kuro-uchi - the word “kuro” means black. This look is traditional and robust, with an unprocessed top part of the blade that has already developed a dark patina.

🦉 During the forging process, the knives are exposed to tremendous heat and flames so that the iron on the surface oxidizes and turns black. During the later processing, the surface is thinned and polished to bring out the reflective and shiny nature of the blade. If the desired end results is the kuro-uchi finish, the upper part of the blade is no longer polished in the later stages of the process.

This look is somewhat robust and organic, but it has a purpose – it will minimize the reactivity of a carbon steel knife and reduce the risk of corrosion compared to knives with a high polish finish. This dark “patina” is also applied to knives made of stainless steel and its sole function is style and aesthetics.

 You can find out more about the final look of the blade in article Blade construction: Blade finish

Knives made of HAP-40 steel were made with professional users in mind. We took advice from our chefs to heart and drew on their extensive experience in using Japanese knives. They are the ones who exactly know what properties a blade must possess so they can prepare food efficiently and effectively. When choosing the material and also design of the blade, we put together our knowledge, our user’s requests and the Japanese tradition in the forging of most demanding materials. And what is the final result? An unsurpassable quality and versatile use in just one, perfect blade!

About Yoshida Hamono:

The knife is manufactured at the smithy of Yoshida Hamono in Japan, a family company with an age-long tradition in manufacturing state-of-the-art tools and Japanese swords, i.e., katanas, by hand. Yoshida Hamono has a great deal of experience forging ZDP-189 steel in the traditional manner.

Specifications:

Blade shape: Petty
Steel type: HAP-40
Hardness (HRC scale): 65-67
Overall length: 265mm (10.4")
Blade length:
135mm (5.3")
Blade height:
30mm (1.2")
Spine thickness: 2.0mm (0.08")
Weight: 100g (3.5 oz)
Handle length: 115mm (4.5")
Handle type / wood:
Japanese / Custom
Blacksmith: Yoshida Hamono


Use & Care:

  • Handwash in warm water and towel dry
  • Use a sharpening stone (not a honing steel!) to sharpen your knife
  • Do not cut frozen foods and meat bones
  • Do not put the knife in a dishwasher
  • Read our comprehensive guide on proper Maintenance of Kitchen Knives.

Still doubting which type of Japanese knife should best fit your needs? We created a quick, 5-steps quiz to help you find the perfect knife based on your cooking skills and the type of food you prepare.

 

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