Install crafty-books-medtosmall by entering the following commands in the terminal:
sudo apt update sudo apt install crafty-books-medtosmall
Description:
Medium-to-small size opening books for crafty chess engine
Opening books that crafty use to evaluate the position during the game. This is the medium-to-small version, occupying 4MB and containing +7500 games computed until the 60th ply.
Version: 1.0.debian1-2
Section: multiverse/games