電光刹歌 (Denkousekka) is a high-speed VOCALOID track produced by Camellia (Masaya Oya) as the fifth entry in Project ONSOKU, a cross-franchise collaboration between Sega's Sonic the Hedgehog and Hatsune Miku. The song launched simultaneously in three Sega rhythm games, maimai DX CiRCLE, CHUNITHM X-VERSE, and ONGEKI Re:Fresh, beginning November 20, 2025. The title is a deliberate wordplay on the Japanese idiom 電光石火 (denkousekka, "lightning speed"), substituting 刹歌 ("instant song") for the original final characters to blend concepts of speed and music. Clocking in at 207 BPM, the track showcases Camellia's characteristic hard-edged electronic production style, dense synth layers, rapid-fire beats, and Miku's processed vocals delivering lyrics that frame the song as a head-to-head race ("Ready, set, go!"). The music video was created by Hiromitsu Kawasaki, Kyoko Miyagawa, カンタロ, and Kazuma Enta, pairing the audio with visuals that echo Sonic Racing: CrossWorlds, the game from which the track originates. In maimai, the DX chart set spans Basic through Master. The Master chart, designed by はっぴー (Happy), stands out within the set for its heavy Slide-note concentration, 132 out of 828 total notes, giving it a distinctive sweeping play pattern that mirrors the song's relentless forward momentum. The Expert chart by Jack counters with a dense Break-note layout (47 notes) that rewards precise timing during climactic sections.