by heart

Also, by rote. From memory; also, mechanically. For example, Betty had trouble learning the song by heart, but her teacher insisted on it, or Japanese schools put heavy emphasis on learning by rote. These terms are often put as know by heart or learn by rote. The first term was already used by Chaucer (in Troilus and Cressida). The variant, also dating from the 1300s, often implies mere memorization without deeper understanding. Both phrases remain in use, although this form of learning is no longer so widespread as it once was. Also see commit to memory.