Rough grinding: 

put blade into rough grinding side, pull knife blade back and forth in constant speed, repeat 3-5 times
Rough grinding is suitable for rough blade knife or the knife using long time but not grind yet
Generally, suit for cleaver knife, chef knife, carving knife and paring knife

Fine grinding: 

put the blade into the fine grinding side, pull knife blade back and forth in constant speed, repeat 3-5 times
Fine grinding side used special ceramic raw material, have nice grinding feature.
Generally use to be repaired the rag after rough grinding, makes the blade more smooth
Using ceramic side for grinding regularly will extend service life of knife

One

Anti-slip ground mat, 

make sharpener stable, 

safe is most important

Two

Knife grinding, combining fine grinding 
and rough grinding  

Three

Ergonomic handle,

to provide best 

sharpening experience