The first chess championships were round-robins. This was the fairest method, since everyone got a shot at testing everyone else. Furthermore, tournaments were social affairs; everyone who gathered together wanted to meet and play everyone else. Over time, the popularity of the game grew. More players reached a level of mastery enabling them to challenge for the title. The system of play was modified slightly: players were divided into sections, each section was a round-robin, and the section winners played off to determine the overall winner.
After World War Two, there was a boom in interest in the game in North America, as emigrants from Europe's chess loving nations came to Canada. Tournament play took off. At the same time, a rating system was established so that players could compare their strength with each other.
The two factors came together in the happy introduction of the Open Championship. In this Swiss tournament, players were ranked by their chess rating. Players of all strengths, and in any number, could now gather together in one competition. The Canadian Open Championship was established in 1956. The problems of how to pair players to determine a winner were solved over the late 1950s and early 1960s in our own Canadian Open Championships by Canada's pioneer in this field, Phil Haley.
With players of all strengths gathered together, there were chances for class players to meet and play much higher rated players, such as Grandmasters. In 1971, the ultimate happened, when reigning World Champion Boris Spassky competed in the Canadian Open Championship. Here he accepts the first round challenge by a Candidate Master from British Columbia.
Peter Danenhower - Boris Spassky
9th Canadian Open Championship, Vancouver, British Columbia, 1971.08.24, Round 1
1. d4 Nf6 2. c4 c5
The first challenge to White's centre.
3. d5 g6 4. Nc3 Bg7 5. Nf3 O-O 6. g3 d6 7. Bg2 e6
The second challenge to White's centre.
8. O-O exd5 9. cxd5 Nbd7
Up to here, White is doing fine, maintaining the initiative from moving first, occupying the centre and taking an advantage in space. Against this, Black is flexible, retaining freedom to choose where to counter-attack: kingside, centre or queenside.
10. Nd2 ?
(White's plan is to play e4 to strengthen P/d5 and to occupy the centre. Perhaps White was afraid that P/e4, d5 needed protection from B/g2, so the diagonal g2-e4 is cleared. But look at the disastrous effects elsewhere: White gives away the initiative by not continuing to develop; B/c1 is prevented from developing on the diagonal that was opened for it; and even the Q/d1, which had an open path, is now blocked. So, the plan is a poor one. The alternative 10. Bf4 would continue piece development, as well as attack P/d6 at the base of Black's pawn chain.)
Black takes the initiative and chooses where to counter-attack: the kingside. This is a natural choice given that Black must play for a win in the tournament.
11. e4 Ne5 12. h3
To keep a piece off g4, but it takes time away from development and weakens the kingside.
Played not so much to attack the centre as to bring the R/f8 into the fray.
13. Kh2 f4 14. Nf3 g5
Committing fully to the attack while risking opening up his own king's position.
15. Qe2 Kh8
A little safety for the king, and makes g8 available to the rook in case it is better placed on the g-file.
16. Bd2 a6
Safeguards the queenside and the centre by taking away the possibility of Nb5; limits White's options for where to play.
To prevent ... b5 and a Black queenside attack with a pawn majority of 3-2.
Not just to make the queenside safe against an annoying a5, which would keep this pawn backward; it also clears the seventh rank for the R/a8 to swing across to the kingside.
18. Nd1 Ra7 19. Bc3 g4
If necessary, this will be a sacrifice to clear the way for the pieces. White has thoughts of winning the pawn; right now it is one attacker against two defenders.
By eliminating a defender and clearing the e2-g4 diagonal at the same time, it becomes two attackers against one defender.
20... Bxe5 21. hxg4 Qg5 22. Bxe5+ dxe5 23. Bf3 ?
(Black's pressure builds and White starts to crack. However, there weren't many good options here. For example, 23. f3 fxg3+ 24. Kxg3 h5 and Black has an easy time to attack, whereas White's pieces are poorly placed to defend.)
23... Nf6 24. Kg2 Nxg4 25. Rh1 Rg7
Right onto the open file, taking advantage of the chances Black created earlier.
26. Ra3 ?
Development completed, at last! However, it's a blunder which permits Black's combination.
26... fxg3 27. fxg3
27... Ne3+ !
Clearing the line for Q/g5 to reach g3; the check saves a tempo.
28. Qxe3 Qxg3+ 29. Kf1 Bg4
(Three attackers, two defenders. The B/f3 cannot move, since it is pinned by R/f8 to K/f1. Also, it cannot be defended again successfully, since on 30. Ke2 Rxf3 the more valuable queen has to re-capture first by 31. Qxf3. So, the sacrificed piece is recovered.)
30. Qf2 Rxf3 31. Rxf3 Qxf3
(The only way out of the mating net is 32. Qxf3 Bxf3 with a double attack on N/d1+R/h1. Moving the rook loses the knight; or 33. Nf2 Bxh1 34. Nxh1 leaves White unable to cope with Black's threats to promote pawns on both the kingside and queenside.)