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Dmt d8c or atoma 400. Personally prefer the atoma as its far lighter doesn't stick and can buy replacement grits for it. Brought the 1200 replacement and stuck it on the back for a double sided hone

If it's anything like the naniwa one I got you may want to take off any sharp or square corners also. I lapped mine on very low grit w&d on a piece of glass. Didn't think much of it so brought a d8c