Similar to the Pirc but more flexible. Black fianchettoes the king's bishop early.
The variations below diverge from the first move, so each has its own page with the full move order, the position it reaches, and a Stockfish evaluation.
All 9 lines can be practised free in the browser: pick a variation, walk it move by move in Learn mode, then drill it from memory until you can play it without prompting.
The Modern Defense is catalogued under ECO codes A04–B06. Individual variations list their own specific code on their page.
Open any variation on Chess Ramp and use Learn mode to walk the line one move at a time, then Drill mode to replay it from memory. Practice runs in your browser with no account required.