電光石火 (Denkousekka) is a high-tempo instrumental track by HiTECH NINJA, an alias of the prolific electronic composer lapix (大渕海斗). Clocking in at 165 BPM with no vocals, the track delivers a relentless barrage of synth stabs, breakbeat-influenced drums, and melodic leads characteristic of lapix's hardcore and EDM style. The title is a Japanese yojijukugo (四字熟語, four-character idiom) that literally translates to "electric light, flint spark," used idiomatically to mean lightning speed or in the blink of an eye, a fitting name for the track's blistering pace. 電光石火 originated as a CHUNITHM Original song, debuting in CHUNITHM AMAZON PLUS before crossing over into maimai でらっくす FESTiVAL on January 20, 2023. It arrived as part of the CHUNITHMちほー2 (CHUNITHM Area 2) event zone, where players could unlock it by reaching distance milestones. Starting with maimai でらっくす BUDDiES, the song became available by default in all regions. Its Master chart, designed by あまくちヘルツ (Amakuchi Hertz), sits at level 14 with a constant of 14.3, a demanding spread that makes heavy use of Slide notes (99 total, the highest count among the four maimai DX charts) alongside dense 16th-note streams. The Expert chart, designed by ロシェ@ペンギン (Rocher@penguin), holds a level 12+ with a 12.8 constant and serves as a preparatory step into the song's high-speed patterns.