Taiko Beats

A three-key drum rhythm game for the browser, inspired by Taiko no Tatsujin — notes scroll vertically down three lanes (left rim / drum center / right rim) toward a hit line, DDR-style. All audio is synthesized live with WebAudio — no external music files, no copyrighted tracks, no build step.

Play it: open index.html or visit the GitHub Pages deployment.

Controls

Lane	Keys
Left rim (Ka)	D or ←
Drum (Don)	F or ↓
Right rim (Ka)	J or →

Judgment windows: Perfect ≤ 50 ms, Good ≤ 110 ms, otherwise Miss. Score, combo, accuracy, and a grade (S/A/B/C/D) are shown on the results screen. Esc quits a song.

Two built-in generated beatmaps are included: Festival Beat (96 BPM) and Thunder Roll (150 BPM).

Beatmap editor

Click Beatmap Editor on the menu:

• Load your own audio file, or use the built-in synthesized drum track
• BPM and offset (ms) settings
• Beat snap: 1/4, 1/8, 1/12, 1/16, 1/24, 1/32, or free placement
• Scrolling timeline with a waveform (or synth-pattern) display
• Click a lane to place a note (snapped); click/right-click a note to delete it
• 1/2/3 or D/F/J to toggle a note at the cursor; Space plays/pauses
• Drag the ruler/waveform to scrub; ←/→ step the cursor by the snap interval
• Test-play launches the map from the cursor position (Esc returns)
• Undo/redo (Ctrl+Z / Ctrl+Shift+Z or Ctrl+Y)
• Save maps to the browser (they appear under "Custom Maps" on the menu); export/import maps as JSON

Map JSON format

{
  "format": "taiko-beats/1",
  "name": "My Map",
  "bpm": 120,
  "offsetMs": 0,
  "lengthMs": 60000,
  "audio": "synth",
  "lanes": 3,
  "notes": [{ "t": 1000, "lane": 1 }]
}

audio is "synth" or "file". File-based maps store only note data — re-load the audio file after importing.

Tech

Plain HTML / CSS / JavaScript on <canvas>. No dependencies, no build step. Deployed via GitHub Pages.

License

MIT — see LICENSE.