Ikazuchi (怒槌) is a high-energy instrumental track composed by Takenobu Mitsuyoshi (光吉猛修), originally created for SEGA's arcade rhythm game CHUNITHM. It holds the distinction of being Mitsuyoshi's first original composition for a SEGA music game, and the piece charges forward at a relentless BPM of 200, built from heavy synthesizers, pounding percussion, and a thunderous, martial atmosphere that matches its name, the kanji 怒槌 evoke a sense of wrathful thunder. The song quickly transcended its origin game: selected as the CHUNITHM representative entry for the 4th Tenkaichi Otogesai (天下一音ゲ祭), it was ported to SOUND VOLTEX IV HEAVENLY HAVEN, GROOVE COASTER 3EX DREAM PARTY, and 太鼓の達人 イエローVer., and later made its way into Arcaea, DJMAX RESPECT V, and オンゲキ. In maimai, 怒槌 arrived with the MiLK PLUS update on December 4, 2018, classified under the ONGEKI & CHUNITHM genre (originally ORIGINAL & JOYPOLIS prior to the でらっくす PLUS category reorganization). The song left an immediate mark on the game's chart landscape: its MASTER chart, credited under the collective pseudonym 譜面ボーイズからの挑戦状 (Challenge from the Fumen Boys), set a new maimai record with 1,188 notes, surpassing the previous high held by larva by 15 notes. The BASIC chart was equally historic, becoming the first in maimai to reach 400 notes and keeping the highest BASIC note count until XaleidoscopiX. Over subsequent version updates, the MASTER chart rose from level 13 through to the current 14+, reflecting both shifting difficulty standards and the chart's enduring physical demands.