On its third album in just over two years, back number hits its groove with Blues. The Japanese rock trio had long been working overtime on the tour circuit, eventually translating its onstage dynamics into 2010’s loose and lively long-player Ato No Matsuri and 2011’s fierce follow-up Super Star. On 2012’s Blues, vocalist-guitarist Iyori Shimizu, bassist Kazuya Kojima, and drummer Hisashi Kurihara retain that spunky sound while seamlessly slipping in silkier strings, heavier grooves, and more bittersweet romance. Love—or the precariousness of it—is often the source of those titular “blues.” Shimizu is a hopeless romantic, professing his adoration in big power ballads and catchy sing-along anthems. He questions the authenticity of those around him—even himself—on the propulsive pop-rock opener “Aoi Haru,” then overthinks the act of holding a crush’s hand on the piano-lined “Watagashi.” Still, the frontman is also acutely self-aware, realizing his power as a songwriter that can inspire others, a sentiment he breathlessly expounds on over Britpop-leaning licks on “Heijitsuno Blues.” Shimizu uses both his voice and guitar to potent effect, twisting his honey-dipped croons into yearning yowls and working his fingers through sizzling solos (as on the swaying paean “Egao”) and acoustic lullabies (like the inspirational rocker “Bokuga Ima Dekirukotoo”). While there’s a sense of melancholy bubbling underneath, there’s a hefty streak of joy and gratitude, too. Throughout, Kojima and Kurihara keep Shimizu on his toes, picking up the pace with punchy pop-punk moves on “Bird’s Sorrow” and sweeping symphonic arrangements on “Nichiyoubi.” As much as the band digs into its rock roots on Blues, the trio also shows off its impressive versatility—something that would soon turn back number into a Japanese powerhouse.