Complex sentence: As a group, they are one of the most successful Japanese rock artists and one of the best selling artists in Japan, having sold over 50 million records and creating the in the mid- 1990s in Japan.
Split into simpler sentences: As a group, they are one of the most successful Japanese rock artists. They are one of the best selling artists in Japan, having sold over 50 million records and creating the in the mid- 1990s in Japan.