Just had a go at etching my shun premier. I don’t use the knife and will be giving it to my daughter with a nakiri of the same make. I just thought that I would personalise them after a good thinning and re profile to get rid of the fat belly. Did the etch with Hydrochloric acid and then sat in coffee for 8 hours. The nakiri is going to sit in the coffee for 2 days to check the difference. When I etched I sat in the acid for 15 minutes then sanded with 600 then acid 15 and sand 1500 then acid 15 and sand 2000 very gently. I then washed with filtered water and into the coffee. It’s not perfect but I quite like it. The photos are the 4 stages on the same side.