The Sinquefield Cup in St Louis, one of the strongest tournaments of all time, has been convincingly won by the Armenian grandmaster and triple Olympiad gold medallist, Levon Aronian. Unusually for such a high-level tournament, a number of games ended in vicious attacks which resulted either in checkmate or decisive material gain. To start with, here is Aronian demolishing the world no. six.
 
Aronian-Caruana: Sinquefield Cup, St Louis 2015 (see diagram 1)
 
The black king has become badly exposed and Aronian now sacrifices material to relocate his pieces in that sector. 25 Ne4 Nd4 26 Qh5 Nxc2 27 Nxg5 Bf5 28 Rf1 Qf6 The key point is that 28 … Bg6 29 Rf7+ mates quickly. 29 Ne6+ Rxe6 30 Rxf5 Qg6 31 dxe6 Qxh5 32 Rxh5 Nd4 33 e7 Ra8 34 Rxe5 Re8 35 Re4 Nf5 36 Be6 Nd6 37 Bd7 Nxe4 38 Bxe8 Kf6 39 Bg6 Black resigns
 
Even more bloodthirsty was the conclusion of the game between So and Nakamura. Regardless of material considerations, Black has staked everything on breaking through with a crushing kingside attack.
 
So-Nakamura: Sinquefield Cup, St Louis 2015 (see diagram 2)
 
Nakamura has already given up two pawns and now tears the white kingside apart with further sacrifices. 26 … Nxe4 27 Rd1 27 fxe4 Rf1+ 28 Kg2 Be3 is overwhelming. 27 … Rxf3 28 Rxd7 Rf1+ 29 Kg2 Be3 30 Bg3 A desperate, but doomed, attempt to block the lines of attack. 30 … hxg3 31 Rxf1 Nh4+ 32 Kh3 Qh6 33 g5 Nxg5+ 34 Kg4 Nhf3 35 Nf2 Qh4+ 36 Kf5 Rf8+ 37 Kg6 Rf6+ 38 Kxf6 Ne4+ 39 Kg6 Qg5 mate
 
The elite tournament in St Louis was the second part of a three-tournament cycle starting in Norway and concluding with the London Classic in December. This is the fulfilment of a dream for the former world champion Garry Kasparov, who wishes to set up a truly professional circuit consisting solely of the world’s top grandmasters.

The format is that each of the three events includes the same nine superstars, while each individual tournament has the right to nominate a wild card. In Norway the wild card was Jan Ludwig Hammer; in St Louis it was Wesley So; and in London it will be our own Michael Adams. The prize fund for the circuit is $1 million.

After two of the three legs the scores of the nine superstars are as follows: Topalov 17, Nakamura 16, Aronian 15, Carlsen 14, Giri 13, Anand and Vachier-Lagrave 12, Caruana 9 and Grischuk 8.
 
Correction. The game that generated last week’s puzzle was in fact Adams-Vachier-Lagrave, Biel 2015.