Synthesis. is an instrumental electronic track by Japanese composer tn-shi, introduced to maimai でらっくす PRiSM PLUS on March 13, 2025. Clocking in at a brisk 180 BPM and running 2 minutes and 41 seconds, the song is built around a driving synth melody and crisp percussion that typifies tn-shi's energetic, arcade-friendly production style. Though the maimai release came in PRiSM PLUS, Synthesis. actually debuted earlier in SEGA's vertical-scrolling rhythm game オンゲキ bright MEMORY on June 20, 2024, before spreading to CHUNITHM VERSE at its launch and finally landing in maimai. The track has had an unusually wide reach beyond SEGA's ecosystem, appearing in rhythm game staples such as Cytus II, Muse Dash, Deemo II, Lanota, Paradigm: Reboot, Taiko no Tatsujin, and vivid/stasis, making it one of the most ported independent compositions in the modern rhythm game scene. Within maimai, the Master chart (level 14, constant 14.1) was designed by サファ太 and features a dense note count of 1,103, with heavy emphasis on Touch notes (127) and Break notes (82) that demand precise multi-finger coordination. The Expert chart (level 12+, constant 12.6) was handled by Jack, who crafted a more measured 645-note layout that still pushes into upper-Expert territory. With no lyrics or vocal samples, Synthesis. relies entirely on its instrumental energy to drive the player experience.