A baren is used to rub paper onto a coloured woodblock. This is a disk about the size of a saucer, usually wrapped in a bamboo leaf, that fits in the palm of the hand.
A printer will have several barens to achieve different effects. These may range from inexpensive machine wrapped card, to a skilfully crafted object made over several weeks. The latter cost anything from £300 to £1000. Ball-bearing barens are also popular.
Before use, the bamboo leaf has some light oil rubbed into it. The force of printing, and possibly dampness from the paper, will eventually split the leaf unless this is done.
A press can be used instead of a baren, but you lose flexibility. Extra emphasis in areas and intended baren marks can be integral to the final work.