• April 7, 2025

  • Once hailed as a “dream steel,” ZDP189 may now be slipping out of reach. If you own a knife made of this steel today, consider yourself lucky.

    Revered among professional bladesmiths and collectors alike, ZDP189 is often referred to as a “legendary steel.” With an astonishing HRC hardness of 65–67 and exceptional edge retention, it has long been a favorite of global knife brands such as Spyderco.

    However, in recent years, there has been a growing chorus of voices suggesting that this remarkable material is disappearing from the market.

    So what’s really happening to ZDP189? Is it still being manufactured?

    Let’s uncover the facts behind the rumors.

  • A Vanishing Legend? The Latest on ZDP189


    ZDP189 is a high-performance powdered steel originally developed and produced by Hitachi Metals (now Proterial Corporation). For many years, it was a preferred choice for premium knives and kitchen blades.

  • However, in 2022, Hitachi Metals was acquired by a foreign consortium led by Bain Capital, and in 2023, the company changed its name to Proterial Corporation. This change in ownership may have significantly impacted the fate of ZDP189.

  • Indeed, since 2021, multiple knife forums and specialist websites have frequently discussed the rumored discontinuation of ZDP189. On the official Spyderco forum, founder Sal Glesser hinted at a shift to K390. In fact, many models that once featured ZDP189 have already transitioned to K390 and other steels.

  • What’s more, major retailers such as Rakuten and KnifeCenter now clearly state that “ZDP189 is discontinued,” with many products being sold only while supplies last. These aren’t just rumors — they reflect real movements in the market.

  • Why Was It Discontinued? The Hidden Strategy

    There has been no official announcement declaring ZDP189 discontinued, but several factors suggest the likelihood:

  • Proterial’s new corporate strategy emphasizes “developing high-margin, sustainable materials.”

    • Proterial’s new corporate strategy emphasizes “developing high-margin, sustainable materials.”
    • While ZDP189 is extraordinarily high-performing, it is also difficult and costly to produce.
    • Foreign ownership tends to favor product portfolios based on profitability.
  • Taken together, these facts point to a strategic rationale: “Niche steels beloved by craftsmen” like ZDP189 may have been phased out in favor of more profitable alternatives.

  • Your Knife Could Become an “Investment Piece”

    As of now, ZDP189 knives can still be found on the market. But it is highly likely that these are remaining inventory from past production — and they’re only going to become harder to find.

    In other words, if you already own a ZDP189 knife, it might soon be regarded as a rare collector’s item — a piece with true investment value, like a classic Ferrari or vintage Rolex.


  • The journey to find a worthy successor to ZDP189 is far from over.

    But this moment — right now — may be your chance to witness the beginning of that new chapter.

ZDP189

The ZDP189 collection introduces knives crafted from ZDP189 stainless steel, notable for its exceptional hardness and sharpness retention. This high purity is achieved through powder metallurgy by Hitachi Metals. The material's robustness, durability, and corrosion resistance make these knives favorites among professional chefs and enthusiasts. Each knife is carefully handcrafted by master craftsmen, ensuring unparalleled quality and performance.

ZDP189

Material of Knife

By introducing the materials used in knives, we aim to help customers understand the quality and performance of knives, enabling them to find the perfect knife that meets their needs and preferences.

Japanese Knife Materials
  • Three Intentions Forged in Fire

    Each time I light the forge and watch the steel glow red, I ask myself three questions.

    Will this blade bring joy and emotion to its user?

    A knife that simply cuts is not enough. It must flow naturally in the cook’s hand, feel balanced, and slice with a sensation that brings satisfaction.

    Only when a blade carries something more than function—something that touches the heart—does it become a true tool.

  • Is this work something I can take pride in among my peers?

    Steel is honest. It gives back only what you put into it. Any compromise will show.

    If the younger craftsmen see my work and say, “I want to be like that someday,” there’s no greater honor.

    Earning the respect of your fellow artisans means constantly re-forging yourself.

    Does this blade contribute to the survival of our workshop?

    No matter how noble the craft, it cannot continue without support.

    A knife must sell, bring satisfaction to the customer, and allow us to buy the next batch of steel.

    It is the daily rhythm of creation and commerce that protects this workshop and nurtures future craftsmen.

    Forging is not simply the act of hammering metal.

    It is the act of engraving one’s resolve and sincerity into steel.

    As long as I stand before the fire, I will hold fast to these three intentions—and meet the steel with everything I have.

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    1. Exceptional Japanese Knives

    Our knives, crafted by Sakai City's master artisans, combine traditional techniques with carefully selected materials, delivering unrivaled sharpness and durability.

  • 2. For a Lifetime of Use

    At KIREAJI, we see knives as lifelong companions. Each knife comes with a free saya, and we offer Honbazuke hand-sharpening by Shiroyama Knife Workshop in Sakai City.

  • 3. Supporting the Joy of Continued Use

    KIREAJI knives are made to grow with you. That’s why we provide trusted after-sales care (fee-based) .