Game VIII of the even-terms Morphy–Paulsen match (First American Chess Congress, New York 1857) — an Irregular (Four Knights) Opening, Paulsen (White); Morphy winning the game and the first prize in the American Tournament. Notes from the 'Book of the First American Chess Congress,' with the Editor's additions.
4.d4We should prefer 4. B. to B's 4th.
10…c6Black now has not only gained the attack, but must win a Pawn immediately.
15.Qxc3Giving up at least the exchange.
24…c5The reader will see, from the accompanying diagram, that Black, owing to the strength of his Pawns on the Queen's flank, already has a virtually won battle.
25.c3If he venture to take the Q's P. with the K's B., he must lose a piece. Had White taken the proffered Pawn with the Bishop, he must have lost the game by the following curious train of play, e.g.,— 25. B. takes P. 25. Q. R. to Q's sq. 26. B. takes R. 26. R. takes B. 27. P. to Q. B's 4th 27. P. takes P. (en passant) 28. B. to Kt's 3rd 28. R. takes R. (ch.) 29. B. takes R. 29. B. to R's 7th 30. K. to Kt's sq. 30. P. to Q. B's 5th 31. K. to B's sq. 31. B. to Kt's 6th, and must win.
26.Bc2If he now capture the Q's P., Black wins at once, thus— 26. K. B. takes Q's P. 26. B. takes K's B. 27. R. takes B. 27. P. to B's 7th 28. R. takes B's P. 28. Q. R. to R's 8th (ch.), queening the Pawn next move.
29…c2Winning a piece by force; for if— 30. B. takes P. 30. R. takes R. (ch.) 31. B. takes R. 31. R. to R's 8th, gaining the Q's B.
31…Ra1Winning the game and the first prize in the American Tournament.
J. Löwenthal, Morphy's Games of Chess (1860) · Public domain · source