Nubatama 1000 Grit Waterstone Gold (Bamboo Series)

This is the exact stone Ken evaluated in his Youtube video entitled "Nubatama 1000 grit Waterstone GOLD - Ume or Bamboo?- Now 1000 Grit Bamboo Gold (YouTube)".   This stone appears to only have been used in the evaluation video.

The Nubatama 1000 Grit Waterstone Gold (later finalized as the Nubatama 1000 Grit Bamboo Gold) is a synthetic ceramic waterstone distributed by Ken Schwartz of Precise Sharpening and vendor Chef Knives To Go. Designed as a fast-cutting medium-grit stone, it is primarily used for primary bevel setup, minor repairs, and edge restoration on high-carbon and stainless steel cutlery.

Background and History

The stone was introduced around 2012 by sharpener and distributor Ken Schwartz during the expansion of the Nubatama series of Japanese synthetic waterstones. Initial evaluation units were distributed as uncategorized test models to evaluate user preferences between two proposed Nubatama sub-lines: Ume and Bamboo. Following positive field evaluations regarding its low-porosity binder and fast cutting speed, the stone was formally integrated into the line as the Nubatama 1000 Grit Bamboo Gold.

Technical Specifications

Physical Characteristics and Performance

Water Absorption and Surface Properties

The stone exhibits low open-cell porosity. Upon initial immersion or surface wetting, water absorption is slow, allowing the surface to hold moisture efficiently without rapid drying. Consequently, the stone operates as a splash-and-go medium, requiring negligible pre-soaking compared to traditional magnesia- or clay-bonded waterstones.

Factory-machined surfaces display a brief initial roughness that quickly wears away during the first sharpening pass, exposing a smooth, uniform working texture beneath.

Abrasion and Feedback

• Stock Removal: The stone is characterized by aggressive stock removal, generating heavy dark swarf immediately upon contact with hard cutlery steels.
• Slurry Dynamics: It produces minimal loose mud (slurry), relying primarily on the firm, exposed abrasive matrix to cut rather than loose abrasive slurry polishing.
• Tactile Feedback: Provides distinct tactile and acoustic feedback, enabling the user to maintain a consistent sharpening angle.

Application and Usage

The stone is intended for general sharpening, burr formation, and minor edge resetting. During testing on acute-angle kitchen knives (such as a Kikuchi knife), the stone raised a consistent burr quickly.

Edges finished on the Nubatama 1000 Gold display a clean, toothy micro-bevel characteristic of a true 1000-grit finish, capable of push-cutting paper and cleanly slicing flexible fibrous materials without requiring finer polishing stones.

Sources & Key Video Timestamps

Primary Source: Nubatama 1000 grit Waterstone GOLD - Ume or Bamboo?- Now 1000 Grit Bamboo Gold (YouTube)

Key Moments & References

• [00:00:00] – Introduction of the prototype stone and initial call for feedback to categorize it into the Ume or Bamboo series.
• [00:00:32] – Initial water porosity test demonstrating slow draw/absorption.
• [00:00:58] – Test sharpening begins on a Kikuchi knife at an acute angle; confirmation of splash-and-go behavior.
• [00:01:45] – Surface texture assessment noting initial factory roughness before self-smoothing.
• [00:01:59] – Rapid swarf generation demonstrating aggressive cutting speed.
• [00:03:15] – Evaluation of low slurry/mud production during heavy use.
• [00:03:47] – Burr formation check and lateral strokes for deburring.
• [00:04:25] – Feedback evaluation noting smooth feel and acoustic feedback.
• [00:05:09] – Edge testing on rolled towels and paper push-cuts.