HAP-40 Petty Black 135mm (5.3") - blade
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:
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.
This knife is without a handle so you can fit your own. Browse our selection of handles and create your own, custom-looking knife! If you would like that we fit the selected handle to the blade for you, select Handle fitting service when adding the blade to the cart.
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 3-5 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.
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).
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.
It has a double bevel (symmetrical) blade.
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.
ABOUT THE BLACKSMITH:
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.
Blade shape: Petty
Steel type: HAP-40
Blade construction: Warikomi / hollow grind / kuro-uchi
Hardness (HRC scale): 68
Overall length: 225mm (8.9")
Blade length: 135mm (5.3")
Blade height: 30mm (1.2")
Spine thickness: 2.0mm (0.08")
Weight: 55g (1.9 oz)
Recommended handle size: no handle
Kanji on the blade:
Blacksmith: Yoshida Hamono
Location of the smithy: SAGA / Saga Prefecture / Japan
☝️ Japanese kitchen knives in our store are handmade from natural materials. Slight variations in color, texture, weight and other dimensions are possible. We try to give a good photographic representation of our products, however computer screen resolution and colors do vary, so products might not look exactly as they are seen on screen.
☝️ THIS KNIFE MAY DEVELOP PATINA
Knives made of carbon steels can, due to their low chromium (Cr) content, discolor and develop patina. The knife is the most sensitive when it is still new and a patina had not developed yet, but later, patina will protect the blade. These types of knives require a touch more care:
✔ Wipe it regularly with a clean and dry cloth (you can also do this during use).
✔ After use, rinse it with lukewarm water and wipe it dry.
✔ Coat it regularly with knife maintenance oil or plain refined sunflower oil.
✔ Store the knife by wrapping it in paper which will absorb moisture and protect the blade.
A patina is a thin layer that forms on the surface of oxidized steel and protects it from further oxidation. The patina should not be confused with rust. Patina protects the blade, while rust causes corrosion and deterioration of material, so it should be removed (see Rust erasers).
→ For in-depth information about patina, read our dedicated post on patina.
GENERAL KNIFE CARE TIPS:
Blade wear depends on the quality of steel, usage and maintenance of the blade. Japanese knives are made of high-quality steels. Follow these tips to keep your Japanese knife in top-notch shape:
✔ Use a wooden, plastic or rubber cutting board.
✔ After use, wash the knives and wipe them dry.
✔ Use a magnetic rack, knife blocks, or use protective knife sheath (saya).
✔ A good cutting technique is your best bet to prolong sharpness.
✔ Use sharpening stones to sharpen the knife.
❗️Don’t leave the knife in the sink. Wash it by hand.
❗️Don’t wash the knife in the dishwasher.
❗️Don’t use the knife on glass, ceramics, marble or steel surfaces.
❗️Don’t scrape the food off the cutting board with the edge of the blade. Use the spine of the knife instead.
❗️Knife is a tool intended for specific use - cutting food. It is not a can opener, screwdriver, trowel, wire cutter, hammer etc.
→ For more details, read our guide
on Maintenance of Kitchen Knives.
🤙 Contact us if you need some help. We reply within 1 business day.
- €10 - flat worldwide rate with DHL Express (express delivery, 2-5 business days).
- FREE - all orders over €300 (DHL Express).
- United Kingdom - shipping to UK costs €15. All orders are shipped with UPS Express (2-3 business days). Free shipping on orders over €300.
- Russia (currently not available) - shipping to Russia costs €40. All orders are shipped with EMS postal service.
DUTIES AND IMPORT TAXES:
We ship all orders DDP (duties & taxes paid). This means you will not be charged for any import fees and taxes (including VAT). All our prices are final. The price you see at checkout is the final price, no hidden costs.
- Europe: 1-2 business days
- US & Canada: 2-4 business days
- Rest of the World: 3-5 business days
Our return policy lasts 30 days. If more than 30 days have gone by since the day you received your order, unfortunately we can’t offer you a refund or exchange.
Knife handles 👇
This blade can be paired with our traditional custom-made maple burl handles
select your favorite
→ TOKYO NIGHT reminds us of the flashing lights of Tokyo’s Harajuku. The color of these handles varies from light to dark grey, with soft or deep hues of red and swirls of cream.
→ OKINAWA REEF transports you to the clear waters of Okinawa island. A soothing, emerald green color. It feels like immersing your hand in shimmering coastal waters during summer.
→ KYOTO SUNSET warms us with the glow of sunset over Kyoto. It feels like holding something smooth and warm in your hand – a glow in the sky at sunset or a burst of bright autumn color.
→ TOTTORI SAND takes us on a walk across the Tottori dunes of western Japan. A sandy brown color is inspired by the infinitely swirly sand dunes.
→ NIKKO MOSS remind us of the ancient moss covering the stone walls of the old temples of Nikko. It is not unlike holding a soft piece of velvet in your hand.
If you like a particular color hue, please contact us before placing an order.
Each knife comes with:
✔️ Instructions and knife care leaflet.
✔️ A preventive Band-Aid – the knives are very sharp! 😉
✔️ Original box from the blacksmith, which we wrap in an old Japanese newspaper sheet – so every knife is ready to be passed on as a gift as soon as it hits your doorstep!
✔️ We also offer a special gift wrapping option with the traditional Japanese washi paper.
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.