Suribachi is a Japanese mortar and pestle of sorts, designed for grinding things into fine pastes, such as sesame seeds, nuts, salad dressings, or even guacamole! It excels at fine grinding as opposed to smashing spices. You'll want to avoid aggressive smashing motions, but smooth grinding motions are perfect!

The pestle is made of Japanese pepper wood, which may impart a very subtle flavour into your food.