That it is very highly developed is shown by the rhythm also. There are rhythms of five and rhythms of seven, which are very difficult to keep, and there are songs in which no rhythm is apparent for some bars, but the musician keeps it in his mind and after several bars he comes in upon the right beat. There are rhythms which do not begin upon the beat, which always mislead the hearer. There are four different kinds of songs: the Dhrupad, the Qawal, the Tumri, and the Ghazal. The Dhrupad requires a special training of the voice, just as it is not everyone's work to sing opera music. The Qawal means imagination, the song of imagination.