Error in Cecil Purdy's Analysis

I'm reading the book How Purdy Won. In Purdy's correspondence game from 1936-7 against G. F. McIntosh (Black) that begins on page 24, the following position was reached after 13...N(a6)c5:



Purdy writes, "And now if 14. exf5 Bxf4 15. Bxf4 Nd3+, and regains the piece with a winning attack." (Purdy doesn't specify which knight would check at move 15.)

However, after 16. Bxd3 Nxd3+ 17. Kf1 Nxf4, White has 18. Qe4+, winning a piece and leaving Black with insufficient compensation. 17...Qa6 (instead of 17...Nxf4) can be met by the cold-blooded 18. Be3! Nxb2+ 19. Kg1, and White is well on the way to consolidating.

Perhaps Black intended to meet 14. exf5 with 14...Nb3!?, which was brought to my attention by the silicon analyst. One point is that after 15. axb3 Qxa1 16. Qxa1 Nc2+, White seems to have nothing better than blocking the f1-bishop by 17. Ke2 (17. Kf2 Bc5+ 18. Kg3 Nxa1 would threaten 19...Nxb3 or 19...Rxd2; 17. Kd1 Nxa1 would threaten 18...Nxb3 or 18...Bxf4). So White should play 15. Qe4+, clearing the rank for 16. Rd1. But 15...Qe5! threatens to win the f4-knight after eliminating both its protectors (by exchanging at d2 and then at e4), leaving White no time for 16. Rd1. So, White would return an exchange by 16. axb3 Nc2+ 17. Kf2 Nxa1 (17...Bc5+ loses even more material after 18. Ke2) 18. Bc4, emerging with two pieces for a rook after Black plays ...Qxe4 and ...Nc2. (See next diagram for the sequence in bold.)



White actually played 14. Nfd5, after which Black finished nicely. Here is the complete game.



Purdy writes, "Black sent the following conditionals: If 19. exd5 Ncd3+ 20. Bxd3 Nxd3+ 21. Ke2 Bb5 22. Qg1 Nf2+ 23. Ke1 O-O, forcing mate or win of the Queen." (See next diagram for this variation.)

@greenpawn34 said

Tim Harding gives the same game with light notes in
his 'Classic Correspondence Miniatures' he makes no
mention on apparent fault in Purdy's note but it does
appear there is an uncharacteristic error in Purdy's analysis.

A good spot. Always worthwhile to check the small print.
I also noted that this game has escaped scrutiny at chessgames.com
even making ...[text shortened]... up, the d3 square hangs, Rfe8+ is
is coming. The position is brimming with tactical ideas.

I had looked at 14...0-0 (after 14. exf5), and it took me a while to find the effective answer 15. Nh5 (which the silicon analyst validated). Still, I agree that castling gives Black practical chances.

This game was played early in Purdy's correspondence career, during which he acknowledges that he hadn't yet realized the time and effort required to excel at that form of contest. I'd guess that this faulty note was based on what he had thought during the game.

Never even saw or considered 15. Nh5. Probably the kind of position a computer
will hang on. These things are good at spotting sac-backs if it gets too hot which
human attackers and defenders rarely see till it's too late.

But OTB v a human I'd take Black, it looks easier to play than White who will
need eyes as big as organ stops to spot all the wee tricks popping up and then.
hopefully, they will react to ghost threats, see things that are not there and panic.
(the keyword is 'hopefully' )

Purdy was a top writer on the game. I have his coverage of the Fischer-Spassky '72. A good book.

The '72 match featured one the biggest publishing gaffes of all time.
Edward Winter put me onto it. 'How on earth could they get that date wrong?'

https://www.chesshistory.com/winter/pics/cn11243_steiner.jpg

@greenpawn34 said
Never even saw or considered 15. Nh5. Probably the kind of position a computer
will hang on. These things are good at spotting sac-backs if it gets too hot which
human attackers and defenders rarely see till it's too late.

But OTB v a human I'd take Black, it looks easier to play than White who will
need eyes as big as organ stops to spot all the wee tricks popping ...[text shortened]... rth could they get that date wrong?'

https://www.chesshistory.com/winter/pics/cn11243_steiner.jpg

I agree about taking Black OTB vs. a human. And I like the simile involving eyes and organ stops. My earlier opinion about Black's prospects after 14...0-0 was meant in the context of playing by correspondence at a high level (which I could have made clearer).

I haven't seen Purdy's book on Fischer-Spassky '73, I mean '72. 8^) That's a world-class typo for sure.

That typo is hilarious. Tucked inside a game note, OK that can be forgiven
but to have it on the cover of the book. Amazing.