After years of honing its rock sound and lyrical sweet talk, back number broke through with 2015’s Chandelier. The fifth full-length from vocalist and guitarist Iyori Shimizu, bassist Kazuya Kojima, and drummer Hisashi Kurihara capped off a year when the group’s soaring slow-build approach to guitar ballads hit a sentimental zenith. While it devoted some space to its swifter, funkier inclinations, the beating heart of the collection remains the big, swelling celebrations of romance and equally large reflections on relationships lost. The singles building up to the release of Chandelier showcase back number’s ballad bona fides, balancing slow-burning guitar builds with romantic lyrics. Acoustic strums and violin swells give a cinematic atmosphere to “Heroine,” a song finding Shimizu pushing the upper register of his voice while singing about an out-of-reach object of affection. “Tegami” recreates the scene of an amicable split, while taking stock of what it all meant. Meanwhile, there’s the bell-buoyed declaration of love “Christmas Song,” a massive hit by the time the album arrived.  The collection also showcases back number’s rocking side. “Siren” busts out with speedy guitar riffs and some of the most energetic drumming of Kurihara’s career, while “Mirror Ball To Cinderella” sees the group set aside the emotional revelations and slow builds for a slinky funk-rock night on the town. But Chandelier mostly highlighted back number’s tender-hearted balladry—the style of song it would become known for in ensuing years.