To see that an artist is really popular and loved in Japan, you should look at DVD sales. Because singles and album sales are always inflated somehow using gimmick. But not every fan is willing to buy expensive DVDs. For example, AKB48 girls can't sell 100K DVDs even if they sell 1 million singles each time. On the contrary, Johnny's groups can sell even the moderately popular ones for 150-200K. Arashi's last 5x20 DVDs have sold 1 million, and their average DVD sales are always between 500-700K. The recent growth of BTS in DVD sales also shows how much they has grown in Japan. It was the first time on the Oricon 2020 list that they had more than 100K sales and this first day sales figure shows that the growth will continue.^^