Original: Since her 1998 debut with the single "Poker Face", Hamasaki has sold over 50 million records in Japan, making her the best selling solo singer in Japanese history and ranking her among the best-selling singers in the country.
Simplified: Since she debuted in 1998 with "Poker Face," Hamasaki sold more than 50 records in Japan. This puts her as one of the highest ranking singers in the country.