Ken Kaufman vs. Cary Utterberg, 1988
22 ... Rb2! 23 Qa8? ...
23 hg+ Qg6 24 Qd5+ Ke7 with advantage, but the text allows a forced mate
23 ... Qc4+ 24 Ke1 ...
1) 24 Kd1 Rd2+ 25 Kd2 Qd3+ 26 Kc1 (26 Ke1 Bg3#) Ba3#
2) 24 Kf2 Rd2+ 25 Kg1 ...
25 ... Rg2+! 26 Kg2 Qe2+ 27 Kg1 (27 Kh3 Qg4#) Qe3+ 28 Kf1 (28 Kg2 Qe2+ 29 Kg1 Bc5#, or 29 Kh3 Qg4#) Qd3+ 29 Kf2 (29 Ke1 Bg3#, or 29 Kg2 Qe2+--finishing as in the line 28 Kg2 Qe2+, or 29 Kg1 Bc5+ 30 Kg2 Qe2+ 31 Kg3 Qg4+ 32 Kh2 Bd6#) Bg3+ 30 Kg1 Qe3+ 31 Kg2 Qf3+ 32 Kh3 Bf2+ 33 Kh2 Qg3#
24 ... Bg3+ 25 Kd1 ...
25 ... Rd2+! 26 Kd2 Qd3+ 27 Kc1 Qc3+ 28 Kb1 ...
28 Kd1 Qd3+ 29 Kc1 Qe3+ transposing to the game
28 ... Qd3+ 29 Kc1 ...
29 Kb2 Be5+ 30 Kc1 Qe3+ 31 Kd1 Qd3+ 32 Ke1 Bg3#, or 32 Kc1 Qc3+ transposing to the game
29 ... Qe3+ 30 Kb2 ...
30 Kd1 or c2 Qd3+ 31 Kc1 Bf4+ 32 Kb2 Be5+ 33 Kc1 Qc3+ 34 Kd1 Qa1+ 35 Kd2 Qa2+ 36 Ke1 Qb1+ 37 Kd2 (37 Ke2 Qd3+ 38 Ke1 Bg3#, or 38 Kf2 Bg3+ 39 Kg1 Qd1#, or finally 37 Kf2 Qc2+ 38 Kf1 [38 Ke1 Bg3+ 39 Kf1 Qf2#, or 38 Kg1 Qd1+ 39 Kf2 Bd4+ 40 Kg3 Qg4+ 41 Kh2 Qh4#] Qd3+ transposing to the main line) Qb2+ 38 Kd1 (38 Ke3 Qc3+ 39 Ke2 Qd3+ winning as in the line 37 Ke2 Qd3+) Qb3+ 39 Ke1 (39 Kc1 Bf4#, or 39 Ke2 Qd3+--again leading to the line 37 Ke2 Qd3+, or 39 Kd2 Bf4+--the same position one move sooner than the main line) Bg3+ 40 Kd2 (40 Kf1 Qd1#, or 40 Ke2 Qd3#) Bf4+ 41 Ke1 Qb1+ 42 Kf2 Qc2+ 43 Kf1 (43 Ke1 Bg3+ 44 Kf1 Qf2#) Qd1+ 44 Kf2 e3#
30 ... Be5+ 31 Kc2 Qd3+ 32 Kc1 Qc3+ 33 Kd1 Qa1+ 34 Ke2 Qa2+ 35 Kf1 Qb1+ 36 Kf2 Qc2+ 37 Kg1 Qd1+ 38 Kf2 Bd4+ 39 Kg3 Qg4+ 40 Kh2 Qh4#