Kumamoto Amakus Binsui (#1500) - AKB657432

Classification

Origin: Amakusa Islands, Kumamoto Prefecture, Japan (天草砥石).
Layer / Type: Binsui-do (天然備水砥 / Medium stone / Chūto).
Grit Rating: Nominal #1500 (typically performs in the #1000–#1500 JIS equivalent range depending on slurry management).
Stamps: Marked  天然備水砥 (Natural Binsui Stone) and 中砥 1500.
Size Category: Japanese 30-gata format (195mm × 62mm × 38mm; 1,138g).
Description
Appearance: Pale cream/buff background speckled with fine natural silica pores, accented by distinct reddish-brown iron oxide banding (tora / tiger striping) across the side and bottom face.
Cut & Form: Crisp, precision-sawn rectangular bench stone block with clean factory-chamfered edges, fully flat, and stamped on the top, side, and heel.
Abrasive Nature: Composed of natural quartz/silica abrasive bound in a medium-soft sedimentary matrix that readily releases fresh cutting particles during work.

Evaluation & Working Characteristics

Role in Progression: Functions as a classic middle-stage stone (Chūto). It serves as the bridge between coarse synthetic/natural shaping stones (#800) and pre-finishing stones like Aoto, Kaisei, or fine nagura stages.
Speed & Feedback: Offers consistent tactile feedback with fast slurry generation. It cuts carbon and mild cladding cleanly without loading up or glazing over.
Scratch Pattern & Finish: Leaves a uniform, hazy, diffuse scratch profile that blends grind marks quickly and sets up the primary bevel for even kasumi contrast on clad and San Mai steels.
Condition & Longevity: Pristine, unspent condition. At 38mm thickness and over 1.1kg, it provides substantial working life for bench use.