The training of double-row keys is basically popular now. The most famous school in Beijing is September Miracle. At present, there are dozens of cooperative schools in China. Now all conservatories of music have started to offer such specialized courses, and 985 and 2 1 1 universities all over the country have also begun to recruit special students. If you learn to learn, you can try to choose famous ones. Of course, it doesn't matter if you learn to play. If you want to play ordinary music, you need to learn music theory. Now I have been practicing double-row keys for 4 years and got a 5-level certificate. Ask me any questions.