The 19-year-old Vietnamese grandmaster Thien Hai Dao gave a demonstration of his powerful and imaginative style in the fourth round of the World Junior Championship in Zagan, Poland.

Black's play in the opening was unconvincing. He should delay castling in this line in favour of a quick Q-side advance. As a result, White was able to carry out his positional plan of Nd5, exd5, Na5 and Nc6, with advantage.

White must have felt he was winning when he played 29.Nd8. Since 29...Qf8 30.Ne6 is fatal, Black had to give up the exchange - and that was when White began to lose track of events.

After 31...Bg7, his queen belongs on d2, protecting a5 and planning Rc1 and Bc3 to contest the power of the bishop on g7.

31.Rd4 also looks odd, but White had spotted, perhaps too late, that 31.Rc1 Qa7! leaves Black threatening both Qxa5 and exchanges on c4 that leave g1 unprotected. At the end, a likely finish would have been 37.Rxe3 Qxe3 (fxe3 also wins) 38.Bd2 Bxb2+ 39.Kxb2 Qd4+ 40.Kb3 Rb8+ 41.Kc2 Rb2+ 42.Kc1 Rxd2 43.Rxd2 Qa1+ and Black wins.

White: Andrei Florean

Black: Thien Hai Dao

1 e4 c5 20 Ka1 axb5

2 Nf3 d6 21 Nc6 Bxg5

3 d4 cxd4 22 Bxb5 e4

4 Nxd4 Nf6 23 fxe4 Bxe4

5 Nc3 a6 24 Rhe1 Nf6

6 Be3 e5 25 Bc4 Re8

7 Nb3 Be7 26 Qd4 Qf7

8 f3 Be6 27 Rg1 Bh6

9 Qd2 0-0 28 Bh4 Nd7

10 0-0-0 b5 29 Nd8 Raxd8

11 g4 Nbd7 30 Bxd8 g6

12 g5 Nh5 31 Ba5 Bg7

13 Kb1 Nb6 32 Qf2 Ne5

14 Nd5 Nxd5 33 Qf1 Rc8

15 exd5 Bd7 34 Rd4 Qa7

16 Na5 Qc7 35 Rxe4 Nxc4

17 c4 f5 36 Rg2 Ne3

18 cxb5 f4 White resigned

19 Bf2 Bf5+