The Opera Game
Paul Morphy vs Duke of Brunswick & Count Isouard (consulting)
Paris (Italian Opera House), 1858
Paris, 1858 — Morphy plays a casual game in a theatre box while the opera runs. Every move develops a piece toward the enemy king; nothing is wasted. It is the clearest short lesson in chess: get everyone into the game, then strike.
Result: 1–0 (White won). This game is in the public domain. Its moves are checked against the on-device engine, so the board is always correct; the commentary is our own.
Sources: Philip W. Sergeant, "Morphy’s Games of Chess" (1916, public domain), game 200 · Wikipedia, "Opera Game" (independent of the Sergeant lineage).