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Hon-Tajima Natural Whetstone #0365

Hon-Tajima Natural Whetstone #0365

$325.00 USD
$325.00 USD
Sale Sold out
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dimensions

• Length: 8-1/4" (210mm)
• Width: 3-1/8" (80mm)
• Height: 2-3/8" (62mm)
• Weight: 5.44 lb (2475g)

Hon-Tajima Natural Whetstone (天然但馬砥石)  


Overview
An authentic, vintage Tajima Toishi (Hon-Tajima) sourced from the defunct quarries of Hyōgo Prefecture. Functioning as a traditional medium-grit stone (Chu-toishi, ~#800–#2,000 grit), Tajima is prized among blade sharpeners and woodworkers for yielding a fast, creamy slurry that leaves a uniform pre-polish and soft kasumi haze on clad steel bevels.  
This is a heavy, oversized block weighing nearly 5.5 lbs with broad working dimensions that easily accommodate full-sized kitchen knives (gyuto, santoku, yanagiba) and large woodworking plane irons (kanna).

 
Specifications
Type: Japanese Natural Whetstone (JNAT) / Medium Grit (Chu-toishi)  
Origin: Tajima (但馬), Hyōgo Prefecture, Japan  
Markings: Original provenance stamp and maker inspection seal  
Dimensions: 8-1/4" × 3-1/8" × 2-3/8" (210 mm × 80 mm × 62 mm)
Weight: 5.44 lb (2,475 g)
Condition & Visual Details
Stamps: Clear, legible black ink provenance and grading seals on the upper surface and side.  
Matrix & Color: Classic pale grey-green/ash base densely peppered with dark mineral speckling.  
Shape & Cut: Oversized bench block with characteristic diagonal quarry saw marks and a natural tapered profile.  
Flaws: Notable triangular breakout/gouge along the mid-top edge and natural edge/corner fractures; unlapped and sold as is.  

care instructions

​Initial Inspection & Cleaning: Before use, gently inspect your Japanese natural whetstone (JNAT) for any loose grit or debris, and wash the surface with clean water and a soft brush.
​Soaking Guidelines: Understand your specific stone's hardness; softer stones (like Aizu or Amakusa) generally require a brief soak of 10 to 20 minutes, while harder, finer finishing stones (like Tomae or Suita) often perform best as splash-and-go stones requiring only surface hydration.
​Avoiding Thermal Shock: Never submerge a cold or dry stone in hot water, and avoid exposing your JNAT to extreme temperature shifts, which can cause cracking or structural failure.
​Slurry Generation: Build a natural abrasive slurry using a diamond plate, coarse stone, or a matching nagura (such as a Tsushima Nagura) to jump-start cutting action and condition the surface for your blade steel.
​Water Maintenance: Keep the stone adequately lubricated with clean water throughout the sharpening session, periodically rinsing away accumulated swarf to maintain optimal feedback and cutting speed.
​Drying Process: After sharpening, rinse the stone thoroughly under clean running water and allow it to dry completely in a well-ventilated, shaded area away from direct sunlight and artificial heat sources.
​Long-Term Storage: Store your dried JNAT in a stable environment where it won't be subjected to heavy impacts, freezing temperatures, or high humidity fluctuations that could compromise its integrity.

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