I bought 1K Gesshin a few years back and don't use it much anymore, since newer acme-brand ~$30 1/6K combo ws works as well or better. 1K GS is a little harder than my various 1K ws, which stay flat better however more prone to glaze over for alloyed blades with hrc over 62rc. Abrasive density of these new crop of ws is as or higher than GS, translate to better abrading/cutting rate.