Kouhei-Shinmatsu ZDP-189 Nakiri Silver 170mm (6.7")

Kouhei-Shinmatsu ZDP-189 Nakiri Silver 170mm (6.7") comes as the culmination of a decade’s worth of expertise gained through selling and working with knives on our part, and the knowledge and mastery of Japanese knife forging passed down through generations within the Suncraft smithy.

ZDP-189 steel knives are extremely rare and are made by Suncraft specifically for SharpEdge. It is a special powder steel, the production of which is extremely expensive and complex, so availability is extremely limited.

Due to our continued and successful collaboration with Suncraft, we decided to honor the founders of the smithy by naming this line of knives after them: Kouhei (耕平) Kawashima, who started Suncraft more than 70 years ago, and his father, Shinmatsu (新松)

ZDP-189 steel has stood the test of time as the ultimate kitchen knife steel and remains a favorite among professional chefs, as well as aspiring home cooks. Therefore, we felt it was appropriate that this nakiri was forged out of the most hard-core (literally) steel! Coming in at 65-67 HRC on the Rockwell scale, these knives are easily one of the hardest knives on offer, so their edge retention is second to none.

In combination with the subtle hammered finish (tsuchime) adorning the blade and the beautiful octagon rosewood handle, these qualities make this nakiri a sure winner!

BLADE SHAPE:
Nakiri is a traditional Japanese knife with a square, thin blade and a deep, flat belly. Since the entire flat edge of the knife touches the cutting board at once, in one clean, vertical movement, there is no need for a horizontal pull or push. This also means that you won’t be turning the vegetable into an “accordion” of pieces still clinging together by a thread. Due to its characteristics, it’s mostly intended to be used for chopping veg, but you can still use it as a good all-rounder in the kitchen.

STEEL:
This knife was forged out of ZDP-189 steel, which falls into the powder steel category. The ZDP-189 steel has gained a reputation as one of the most technologically advanced steels in Japanese knifemaking, due to its unique characteristics. The carbon (C) content is around 3%, meaning it can be treated to extreme hardness (65-67 HRC), which results in extended sharpness retention. ZDP-189 steel is also highly corrosion resistant due to its high chromium (Cr) content of 20%. Because of its composition, though, it can be hard to treat and forge, so it can only be entrusted to the most experienced blacksmiths.

The steel contains as much as 3% Carbon (C), which is one of the main elements contributing strength and typically found in amounts of up to only 1% in other types of solid steel, while the Chromium (Cr) content, which prevents corrosion, amounts to nearly 20%. It also features 0.60% Tungsten (W), which considerably increases the abrasion resistance of steel, 1.4% Molybdenum (Mo), which helps to preserve the strength and power of steel under variable temperatures, and 0.10% Vanadium (V), the key element in increasing steel strength. Heat treatment produces steel with a hardness of 65-67 HRC.
ZDP-189 composition: C 3.00 % | Cr 20.00 % | W 0.60 % | Mo 1.40 % | V 0.10 % | Mn 0.50 % | Si 0.40 %

Read more on Steel: The Heart of Japanese knives.

LAMINATION:
The technique used to laminate this blade is called san-mai. The core of the blade, which is made of harder (and subsequently more fragile) steel, is sandwiched between two layers of softer steel. This results in a blade that is more flexible, and therefore less prone to breakage and other outside factors.

→ Read more on Blade construction: Lamination.

GEOMETRY:
It has a double bevel (symmetrical) blade. During use, double-bevel knives slide downwards towards the cutting board without swerving to the side. This results in fluid, even cuts. Double-bevel blades are also much easier to maintain, as they are much easier to sharpen than single-bevel blades.

→ Read more on Blade Geometry.

BLADE FINISH:
The upper part of the blade was treated with hammer blows, which resulted in an intricate tsuchime (hammered) finish. The lower half is polished down to the hairline, which is the curvy line marking the border between the laminated part of the blade (jigane) and its core (hagane). The kanji on the blade reads “Kouhei-Shinmatsu 耕平新松", paying homage to the founders of the Suncraft smithy.

→ Read more on Blade construction: Blade finish.

HANDLE:
Traditional rosewood Japanese (Wa) handle with a black pakka wood ferrule. Its octagonal shape makes it especially ergonomic and comfortable to use in either hand.