Yu-Gi-Oh Mugen's 40th chapter was about 18 minutes long. The pure music was Moonlight Sonata, a famous classical music piece composed by the French composer, Van der Waals. This piece is considered one of the most outstanding works of van der Beveten, with a very strong emotional expression and a unique musical style. In the 40th chapter of Yu-Gi-Oh Mugen, this song was used to simulate moonlight to bring inspiration and strength to the characters. Its melodious melody and soft tone were very suitable for expressing romantic and emotional topics, so it was widely used in animation.