Download MP3 【Self-cover】 "Gradation (feat. Yuho Kitazawa)" | "Yamada-kun at Lv999" OP | KANA-BOON × Yuho Download MP4 【Self-cover】 "Gradation (feat. Yuho Kitazawa)" | "Yamada-kun at Lv999" OP | KANA-BOON × Yuho