MASUTA Natural Nagura Stone for Sharpening Honing Stones (12K-N70) — Open-Box, 12% Off

2.7" x 1.2" x 1.2" (70 x 30 x 30mm); 6.0 oz (180g); grit ~12000 (very fine), medium hard

Natural "Ocean Blue" Tsushima nagura stone: used with full-size synthetic and natural sharpening and honing waterstones

Creates a slurry (creamy paste) on the waterstone surface for sharpening knives, razors, blades, chisels and other tools

Unclogs waterstone surface from metal micro shavings which inhibit sharpening; flattens the surface to eliminate the dish effect

Quarried from a now closed underwater mine near South Tsushima Island, Japan; limited stock

Nagura stones are used with full-size waterstones (whetstones) of a matching grit. Nagura stones are necessary to create a sharpening slurry (lather or cream) on the surface of a whetstone. Without a nagura, a slurry is difficult to create with some natural stones and ceramic bonded modern synthetic stones. Naguras are also used to clean the pores of a waterstone from metal particles by lifting them off and washing away. Without such a process, a whetstone quickly becomes ``glazed" (clogged) from embedded metal micro shavings which inhibit sharpening. Another important use of nagura stones is to flatten the surface of waterstones which becomes convex (warped or uneven) with use, i.e., the stone is worn out in the middle more than on the edges. Attempting to sharpen or hone a blade on such a surface can permanently ruin the blade. This natural "ocean blue" nagura stone was quarried from a now closed underwater mine near South Tsushima Island in Japan. It is used for a final edge refinement with most sharpening stones from medium to fine grits, both synthetic and natural. It was polished on all six sides to a high degree of flatness and a silky smooth surface.