This is not real pepper, but it is so called because its berries look like berries of pepper. It is very often employed in Chinese cuisine, in particular in the Sichuan province in the South-Western part of the country.
The cuisine of this province is characterized by very strong and hot taste, but at the same and time fresh and fragrant. Sichuan pepper, in its turn, has a lemon aftertaste, which goes very well with ginger, lemongrass and citrus peel (typical components themselves of this cuisine).
Sichuan pepper can usually be bought in dried berries and one of the best ways of bringing out its taste is to toast the berries in a pan to bring out the flavor and then to grind them in a mortar.