KEG: Like transpose, I am surprised that Tchigorin played 3. Nc3 four times at London 1899 (getting one draw and three loses). In the game against Cohn, he got a bad game despite Cohn's poor opening play. Tchigorin followed his weak 3. Nc3 with the even worse 4. d3 (4. Nf3 was best), but Cohn responded with 4...Nd4 allowing Tchigorin to get his Queen off e2 with 5. Qd1.
Tchigorin had a good game thereafter until his horrible 11. Nd1 (11. Qg3 or 11. 0-0 were obviously better).
Tchigorin most have been out of sorts as a result of Cohn's disrespectful 3...e5. Beginning with 23. a3, Tchigorin unleashed a series of terrible moves that left him hopelessly lost. Almost anything was better than 23. a3 (23. b3; 23. Ne3; or 23. Rab1 for instance). Even with this weak move, Tchigorin was not yet lost. Cohn's equally weak response (23...f5 instead of something sensible like 23...Ng5 or 23...0-0) got Tchigorin back in the hunt, and even left him with a small edge. But then Tchigorin went loony.
25. Bf3 forfeited any even small advantage Tchigorin had (Chessical's 25. b4 is far better). 26. Kh1 (instead of the indicated 26. Bc6) gave Tchigorin a lost or nearly lost position, 27. Bc6 (one move too late!) was a blunder (27. Bxg4 was necessary).
After 28. Rg1 (28. Bd5 was Tchigorin's last possible chance to get back in the game) it was all over but the shouting.
29. Ba4 shows that Tchigorin must have given up. Although Cohn somehow missed the crushing 29...g3, the game was definitely over.
After 32. Bb7 Rc7, Tchigorin got annihilated.
Whether it was Cohn's presumptuous 3...e5 or something else that got Tchigorin off track, the game record is not characteristic of this very talented player.