Katana sharpening. Sorbus water stone Versus Winco 12 inch stone.

Winco 12-Inch Fine/Grain Knife Sharpening Stone, Medium
https://www.amazon.com/Winco-12-Inch-Grain-Sharpening-Medium/dp/B0016J5OFU/ref=sr_1_1?ie=UTF8&qid=1527714071&sr=8-1&keywords=Winco+12+inch+stone