System “Z” is a high-speed fusion track composed by Jimmy Weckl, first added to maimai GreeN on October 24, 2013 as one of the version's flagship boss songs. Running 1:53 at 147 BPM, the piece draws on Weckl's dual background as both a brass player and guitarist, weaving brisk guitar phrases through shifting time signatures and tightly packed break sections. The composer described the image behind the song as a "final system", a centralized control room where a player intelligently manages a sea of instruments and displays. Weckl has also clarified that the "Z" in the title should be pronounced "zee" (American English), not "zed." System “Z” occupies an important place in maimai history. Its MASTER chart, co-designed by 譜面-100号 and はっぴー (credited together under the joint pseudonym "合作だよ" before PRiSM PLUS), was one of the first two charts ever rated Level 12 in the maimai series, alongside Garakuta Doll Play. The chart introduced a signature pattern of overlapping 16th-note triple-slide runs, a novel design motif for the GreeN era that later resurfaced in tracks like Prophesy One and PANDORA PARADOXXX. The song originally required 100,000 maimile to unlock, the steepest cost of any GreeN song at the time, and became freely available by default starting with maimai ORANGE.